Functionalized fluoropolymers and electrolyte compositions

ABSTRACT

Provided herein are functionally substituted fluoropolymers suitable for use in liquid and solid non-flammable electrolyte compositions. The functionally substituted fluoropolymers include perfluoropolyethers (PFPEs) having high ionic conductivity. Also provided are non-flammable electrolyte compositions including functionally substituted PFPEs and alkali-metal ion batteries including the non-flammable electrolyte compositions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to the following U.S. Provisionalpatent applications: U.S. Provisional Patent Application No. 62/111,213,filed Feb. 3, 2015, titled “FUNCTIONALIZED FLUOROPOLYMERS ANDELECTROLYTE COMPOSITIONS,” U.S. Provisional Patent Application No.62/130,238, filed Mar. 9, 2015, also titled “FUNCTIONALIZEDFLUOROPOLYMERS AND ELECTROLYTE COMPOSITIONS,” U.S. Provisional PatentApplication No. 62/147,053, filed Apr. 14, 2015 and also titled“FUNCTIONALIZED FLUOROPOLYMERS AND ELECTROLYTE COMPOSITIONS,” U.S.Provisional Patent Application No. 62/111,217, filed Feb. 3, 2015,titled “FUNCTIONALIZED FLUOROPOLYMERS,” U.S. Provisional PatentApplication No. 62/147,047, filed Apr. 14, 2015, also titled“FUNCTIONALIZED FLUOROPOLYMERS,” and U.S. Provisional Patent ApplicationNo. 62/211,412, filed Aug. 28, 2015, titled “FUNCTIONALIZED PHOSPHORUSCONTAINING FLUOROPOLYMERS.” Each of these applications is incorporatedby reference herein in its entirety.

BACKGROUND

Lithium-ion (Li-ion) and other alkali metal salt batteries are of greatinterest as a renewable energy source. Li-ion batteries are the dominantsecondary battery for consumer electronics, and have potential for otherapplications such as energy storage. However, commercially availableLi-ion batteries typically include electrolytes having high volatilityand flammability. In faulty batteries or batteries exposed to extremeconditions, these electrolytes can cause serious fires. These safetyconcerns limit the use of Li-ion battery technology in fields that uselarge-scale batteries including home and grid storage and transportationapplications.

SUMMARY

Aspects of the disclosure relate to functionally substitutedfluoropolymers. In some embodiments, the functionally substitutedfluoropolymers described herein comprise compounds of Formula I orFormula II:

R_(f)—X_(o)—R′  (I)

R″—X_(m)—R_(f)—X_(o)—R′  (II)

wherein:

R_(f) is a fluoropolymer (e.g., a perfluoropolyether) backbone;

X is an alkyl, fluoroalkyl, ether, or fluoroether group, wherein ‘m’ and‘o’ may each be independently zero or an integer≧1; and

R′ and R″ are each independently functionally substituted aliphatic,alkyl, aromatic, heterocyclic, amide, carbamate, carbonate, sulfone,phosphate, phosphonate, or nitrile containing groups. In some aspects,the fluoropolymer backbone (‘R_(f)’) according to Formula I and FormulaII is a perfluoropolyether (PFPE). In some aspects, the fluoropolymerbackbone (‘R_(f)’) according to Formula I and Formula II may have amolar mass or number average molecular weight (M_(n)) from about 100g/mol to 5,000 g/mol, including each integer within the specified range.In some aspects, the functionally substituted perfluoropolyether (i.e.,R_(f)—X_(o)—R′ or R″—X_(m)—R_(f)—X_(o)—R′) according to Formula I andFormula II may have a molar mass or M_(n) from about 150 g/mol to 5,000g/mol, including each integer within the specified range.

In some embodiments, the functionally substituted fluoropolymersdescribed herein comprise compounds of Formula III and Formula IV:

R_(f)—X_(o)—R′—(X_(t)—R_(a))_(q)  (III)

(R_(b)—X_(s))_(p)—R″—X_(m)—R_(f)—X_(o)—R′—(X_(t)—R_(a))_(q)  (IV)

wherein:

R_(f) is a fluoropolymer (e.g., a perfluoropolyether) backbone;

X is an alkyl, fluoroalkyl, ether, or fluoroether group, wherein ‘s,’‘m’, ‘o’, and ‘t’ may each be independently zero or an integer≧1; and

R′ and R″, and R_(a) and R_(b) are each independently functionallysubstituted aliphatic, alkyl, aromatic, heterocyclic, amide, carbamate,carbonate, sulfone, phosphate, phosphonate, or nitrile containinggroups, wherein ‘p’ and ‘q’ may each be an integer≧1. In some aspects,the fluoropolymer backbone (‘R_(f)’) according to Formula III andFormula IV is a perfluoropolyether. In some aspects, the fluoropolymerbackbone (‘R_(f)’) according to Formula III and Formula IV may have amolar mass or number average molecular weight (M_(n)) from about 100g/mol to 5,000 g/mol, or 200 g/mol to 5000 kg/mol, including eachinteger within the specified range. In some aspects, the functionallysubstituted perfluoropolyether (i.e., R_(f)—X_(o)—R′—(X_(t)—R_(a))_(q)or (R_(b)—X_(s))_(p)—R″—X_(m)—R_(f)—X_(o)—R′—(X_(t)—R_(a))_(q) accordingto Formula III and Formula IV may have a molar mass M_(n) from about 200g/mol to 5,000 g/mol, including each integer within the specified range.

One aspect of the disclosure relates to functionally substitutedperfluoropolyethers according to Formula VIII:

R′—X—R_(f)  (VIII)

-   -   wherein    -   R′ is an unsubstituted lower alkyl linear carbonate group, X is        an alkyl, alkoxy, or ether group, and R_(f) is a branched or        unbranched linear perfluoropolyether having a molar mass of        between 200 g/mol and 550 g/mol.

In some embodiments of a functionally substituted perfluoropolyetheraccording to Formula VIII, R′ is ethyl carbonate or methyl carbonate. Insome embodiments of a functionally substituted perfluoropolyethersaccording to Formula VIII, R_(f) has no more than two ether units. Insome embodiments, R_(f) has two at least two ether subunitsindependently selected from —(CF₂CF(CF₃)O)—, —(CF(CF₃)CF₂O)—,—CF(CF₃)O—, —(CF₂O)—, or —(CF₂CF₂O)—. In some embodiments, R_(f) has oneor more ether subunits of —(CF₂CF₂O)—. In some embodiments, R_(f) hasone or more ether subunits of —(CF₂CF(CF₃)O)—. In some embodiments,R_(f) has one or more ether subunits of —(CF(CF₃)CF₂O)—. In someembodiments, R_(f) has one or more ether subunits of CF(CF₃)O. In someembodiments, R_(f) has one or more ether subunits of —(CF₂O)—. In someembodiments, R_(f) is —CF₂OCF₂CF₂OCF₃. In some embodiments, R_(f) is—CF₂OCF₂CF₂OCF₂CF₂CF₂CF₃. In some embodiments, R_(f) is—CF₂OCF₂CF₂OCF₂CF₂OCF₂CF₂CF₂CF₃. In some embodiments, R_(f) is—CF₂OCF₂CF₂OCF₂CF₂O₂CF₃. In some embodiments of a functionallysubstituted perfluoropolyether according to Formula VIII, R_(f) isunbranched or if branched, the branch point is at least two chain unitsaway from R′. In the same or other embodiments, X may be CH₂, CH₂CH₂,CH₂O, or CH₂CH₂O.

In some embodiments of a functionally substituted perfluoropolyetheraccording to Formula VIII, R_(f) has a molar mass of between 200 g/moland 500 g/mol, between 200 g/mol and 450 g/mol, between 200 g/mol and400 g/mol, between 200 g/mol and 350 g/mol, or between 200 g/mol and 300g/mol.

In some embodiments of a functionally substituted perfluoropolyetheraccording to Formula VIII, R′ is a methyl or ethyl carbonate group,R_(f) is unbranched or if branched, the branch point is at least twochain units away from R′, and X is CH₂, CH₂CH₂, CH₂O, or CH₂CH₂O. Insome embodiments of a functionally substituted perfluoropolyetheraccording to Formula VIII, R′ is a methyl carbonate group, R_(f) isunbranched or if branched, the branch point is at least two chain unitsaway from R′, and X is CH₂.

In some embodiments of a functionally substituted perfluoropolyetheraccording to Formula VIII, the functionally substitutedperfluoropolyether is according one of structures S5, S6, S7, or S7Adepicted below.

Another aspect of the disclosure relates to a functionally substitutedperfluoropolyether according to Formula I, above, wherein thefunctionalized perfluoropolyether exhibits a viscosity of less than 10cP at 20° C. and 1 atm. In some embodiments, the functionallysubstituted perfluoropolyether exhibits a viscosity of less than 5 cP at20° C. and 1 atm. In some embodiments, the functionally substitutedperfluoropolyether exhibits a viscosity of less than 3 cP at 20° C. and1 atm.

Another aspect of the disclosure relates to a non-flammable electrolytecomposition comprising: an electrolyte liquid comprising a functionallysubstituted perfluoropolyether according to Formula VIII and an alkalimetal salt. In some embodiments, the functionalized perfluoropolyethercomprises about 30% to about 85% of the electrolyte composition. In someembodiments, the functionalized perfluoropolyether comprises about 40%to about 85% of the electrolyte composition. In some embodiments, thefunctionalized perfluoropolyether comprises is the largest component byweight of the electrolyte solvent.

In some embodiments of the non-flammable electrolyte composition, R′ isethyl carbonate or methyl carbonate. In some embodiments, R_(f) has nomore than two ether units. In some embodiments, R_(f) has two at leasttwo ether subunits independently selected from —(CF₂CF(CF₃)O)—,—(CF(CF₃)CF₂O)—, —CF(CF₃)O—, —(CF₂O)—, or —(CF₂CF₂O)—. In someembodiments, R_(f) has one or more ether subunits of —(CF₂CF₂O)—. Insome embodiments, R_(f) has one or more ether subunits of—(CF₂CF(CF₃)O)—. In some embodiments, R_(f) has one or more ethersubunits of —(CF(CF₃)CF₂O)—. In some embodiments, R_(f) has one or moreether subunits of —CF(CF₃)O. In some embodiments, R_(f) has one or moreether subunits of —(CF₂O)—. In some embodiments, R_(f) is—CF₂OCF₂CF₂OCF₃. In some embodiments, R_(f) is —CF₂OCF₂CF₂OCF₂CF₂CF₂CF₃.In some embodiments, R_(f) is —CF₂OCF₂CF₂OCF₂CF₂OCF₂CF₂CF₂CF₃. In someembodiments, R_(f) is —CF₂OCF₂CF₂OCF₂CF₂O₂CF₃. In some embodiments,R_(f) is unbranched or if branched, the branch point is at least twochain units away from R′. In the same or other embodiments, X may beCH₂, CH₂CH₂, CH₂O, or CH₂CH₂O.

In some embodiments of the non-flammable electrolyte composition, R_(f)has a molar mass of between 200 g/mol and 500 g/mol, between 200 g/moland 450 g/mol, between 200 g/mol and 400 g/mol, between 200 g/mol and350 g/mol, or between 200 g/mol and 300 g/mol.

In some embodiments of the non-flammable electrolyte composition, R′ isa methyl or ethyl carbonate group, R_(f) is unbranched or if branched,the branch point is at least two chain units away from R′, and X is CH₂,CH₂CH₂, CH₂O, or CH₂CH₂O. In some embodiments, R′ is a methyl carbonategroup, R_(f) is unbranched or if branched, the branch point is at leasttwo chain units away from R′, and X is CH₂.

In some embodiments of the non-flammable electrolyte composition, thefunctionally substituted perfluoropolyether is according one ofstructures S5, S6, S7, or S7A depicted below.

In some embodiments of the non-flammable electrolyte composition, thefunctionally substituted perfluoropolyether exhibits a viscosity of lessthan 10 cP at 20° C. and 1 atm. In some embodiments, the functionallysubstituted perfluoropolyether exhibits a viscosity of less than 5 cP at20° C. and 1 atm. In some embodiments, the functionally substitutedperfluoropolyether exhibits a viscosity of less than 3 cP at 20° C. and1 atm.

In some embodiments of the non-flammable electrolyte composition, thealkali metal salt comprises a lithium salt or a sodium salt. In someembodiments, the alkali metal salt is a lithium salt comprising LiPF₆ orLiTFSI or a mixture thereof. In some embodiments, the electrolyte liquidfurther comprises further comprising one or more of a conductivityenhancing additive viscosity reducer, a high voltage stabilizer, awettability additive, or a flame retardant, or a mixture or combinationthereof. In some embodiments, the electrolyte liquid further comprises aconductivity enhancing additive selected from ethylene carbonate (EC),propylene carbonate (PC), butylene carbonate (BC), fluoroethylenecarbonate, γ-butyrolactone, or a mixture or combination thereof. In someembodiments, the conductivity enhancing additive comprises about 1% toabout 40% of the non-flammable electrolyte composition. In someembodiments, the conductivity enhancing additive comprises about 5% toabout 40% of the non-flammable electrolyte composition. In someembodiments, the electrolyte liquid comprises a high voltage stabilizerselected from 3-hexylthiophene, adiponitrile, sulfolane, lithiumbis(oxalato)borate, γ-butyrolactone,1,1,2,2-Tetrafluoro-3-(1,1,2,2-tetrafluoroethoxy)-propane, ethyl methylsulfone, or trimethylboroxine or a mixture or combination thereof. Insome embodiments, the electrolyte liquid comprises a wettabilityadditive selected from triphenyl phosphite, dodecyl methyl carbonate,methyl 1-methylpropyl carbonate, methyl 2,2-dimethylpropanoate, orphenyl methyl carbonate or a mixture or combination thereof. In someembodiments, electrolyte liquid comprises a flame retardant additiveselected from trimethylphosphate, triethylphosphate, triphenylphosphate, trifluoroethyl dimethylphosphate,tris(trifluoroethyl)phosphate, or mixture or combination thereof. Insome embodiments, the viscosity reducer, high voltage stabilizer, andwettability additive each independently comprise about 0.5-6% of thenon-flammable liquid or solid electrolyte composition and the flameretardant comprises about 0.5-20% of the non-flammable liquid or solidelectrolyte composition. In some embodiments, the electrolyte liquidfurther comprises a phosphate or phosphonate-terminatedperfluoropolymer.

In some embodiments, the non-flammable electrolyte composition has aflash point greater than 100° C. In some embodiments, the non-flammableelectrolyte composition has a flash point greater than 110° C. In someembodiments, the non-flammable electrolyte composition has a flash pointgreater than 120° C. In some embodiments, the non-flammable electrolytecomposition has self-extinguishing time of zero. In some embodiments,the non-flammable electrolyte composition does not ignite when heated toa temperature of about 150° C. and subjected to an ignition source forat least 15 seconds. In some embodiments, the non-flammable electrolytecomposition has an ionic conductivity of from 0.01 mS/cm to about 10mS/cm at 25° C.

Another aspect of the disclosure relates to a non-flammable electrolytecomposition comprising: an alkali metal salt; and an electrolyte solventcomprising a functionally substituted perfluoropolyether and one or moreC1-C10 cycloalkyl carbonates, wherein the functionally substitutedperfluoropolyether comprises between 30 wt % and 95 wt % of the solvent,the one or more C1-C10 cycloalkyl carbonates comprises at least 5 wt %by weight of the solvent, and the functionally substitutedperfluoropolyether is the largest component by weight of the solvent,wherein the functionally substituted perfluoropolyether is according toFormula (I) or (II) below:

R_(f)—X_(o)—R′  (I)

R″—X_(m)—R_(f)—X_(n)—R′  (II)

-   -   wherein R_(f) is a perfluoropolyether backbone;    -   X is an alkyl, fluoroalkyl, ether, or fluoroether linking group,        wherein ‘m’ and ‘o’ are each zero or an integer≧1; and    -   R″ and R′ are each carbonate containing groups, wherein R′ is an        unsubstituted lower alkyl carbonate group.

In some embodiments, the one or more C1-C10 cycloalkyl carbonatescomprises at least 15 wt % by weight of the solvent. In someembodiments, the one or more C1-C10 cycloalkyl carbonates comprises atleast 20 wt % by weight of the solvent. In some embodiments, the one ormore C1-C10 cycloalkyl carbonates comprises at least 30 wt % by weightof the solvent. In some embodiments, the one or more C1-C10 cycloalkylcarbonates comprises ethylene carbonate (EC), fluoroethylene carbonate(FEC), propylene carbonate (PC), or butylene carbonate (BC).

In some embodiments, the one or more C1-C10 cycloalkyl carbonatescomprises ethylene carbonate (EC), with the ethylene carbonate comprisesbetween 5 wt % and 30 wt % of the solvent. In some embodiments, theethylene carbonate comprises between 10 wt % and 30 wt % of the solvent.In some embodiments, the ethylene carbonate comprises between 15 wt %and 30 wt % of the solvent.

In some embodiments, the electrolyte solvent further comprises furthercomprising one or more of a conductivity enhancing additive, viscosityreducer, a high voltage stabilizer, a wettability additive, or a flameretardant, or a mixture or combination thereof. In some embodiments, theelectrolyte solvent further comprises γ-butyrolactone (GBL). In someembodiment, the electrolyte solvent further comprises a high voltagestabilizer selected from 3-hexylthiophene, adiponitrile, sulfolane,lithium bis(oxalato)borate, γ-butyrolactone,1,1,2,2-Tetrafluoro-3-(1,1,2,2-tetrafluoroethoxy)-propane, ethyl methylsulfone, or trimethylboroxine or a mixture or combination thereof. Insome embodiments, the electrolyte solvent comprises a wettabilityadditive selected from triphenyl phosphite, dodecyl methyl carbonate,methyl 1-methylpropyl carbonate, methyl 2,2-dimethylpropanoate, orphenyl methyl carbonate or a mixture or combination thereof. In someembodiments, the electrolyte solvent further comprises a wettabilityadditive selected from the group consisting of triphenyl phosphite,dodecyl methyl carbonate, methyl 1-methylpropyl carbonate, methyl2,2-dimethylpropanoate, or phenyl methyl carbonate or a mixture orcombination thereof. In some embodiments, the electrolyte solventcomprises a flame retardant additive selected from trimethylphosphate,triethylphosphate, triphenyl phosphate, trifluoroethyldimethylphosphate, tris(trifluoroethyl)phosphate, or mixture orcombination thereof. In some embodiments, the solvent further comprisesa viscosity reducer selected from the group consisting ofperfluorotetraglyme, γ-butyrolactone, trimethylphosphate, dimethylmethylphosphonate, difluoromethylacetate, fluoroethylene carbonate(FEC), and vinylene carbonate (VC).

In some embodiments, the electrolyte solvent further comprises anon-carbonate-containing functionally substituted perfluoropolymer etherhaving one or more aliphatic, alkyl, aromatic, heterocyclo, amide,carbamate, sulfone, phosphate, phosphonate, or nitrile terminal endgroups. In some embodiments, the non-carbonate-containing functionallysubstituted perfluoropolymer ether comprises between 5 wt % and 25 wt %of the solvent.

In some embodiments, the non-flammable electrolyte composition has aflash point greater than 100° C. In some embodiments, the non-flammableelectrolyte composition has a flash point greater than 110° C. In someembodiments, the non-flammable electrolyte composition has a flash pointgreater than 120° C. In some embodiments, the non-flammable electrolytecomposition has self-extinguishing time of zero. In some embodiments,the non-flammable electrolyte composition does not ignite when heated toa temperature of about 150° C. and subjected to an ignition source forat least 15 seconds. In some embodiments, the non-flammable electrolytecomposition has an ionic conductivity of from 0.01 mS/cm to about 10mS/cm at 25° C.

In some embodiments of the non-flammable electrolyte composition, thealkali metal salt comprises a lithium salt or a sodium salt. In someembodiments, the alkali metal salt is a lithium salt comprising LiPF₆ orLiTFSI or a mixture thereof.

Another aspect of the disclosure is a non-flammable electrolytecomposition including an electrolyte liquid having acarbonate-terminated perfluoropolymer and a phosphate-terminated orphosphonate-terminated perfluoropolymer is provided. The electrolyteliquid may further include one or more additives. In some embodiments,the electrolyte composition includes an alkali metal salt. In someembodiments, the liquid is homogenous in the absence of an alkali metalsalt at 25° C.

In the same or other embodiments, the weight ratio of thecarbonate-terminated perfluoropolymer to the phosphate-terminated orphosphonate-terminated perfluoropolymer is at least 1.2:1. In the sameor other embodiments, the weight ratio of the carbonate-terminatedperfluoropolymer to the phosphate-terminated or phosphonate-terminatedperfluoropolymer is at least 1.4:1. In the same or other embodiments,the weight ratio of the carbonate-terminated perfluoropolymer to thephosphate-terminated or phosphonate-terminated perfluoropolymer is atleast 1.6:1.

In the same or other embodiments, together the carbonate-terminatedperfluoropolymer and phosphate-terminated or phosphonate-terminatedperfluoropolymer constitute at least 50% by weight of the electrolyteliquid. In the same or other embodiments, together thecarbonate-terminated perfluoropolymer and phosphate-terminated orphosphonate-terminated perfluoropolymer constitute at least 60% byweight of the electrolyte liquid. In the same or other embodiments,together the carbonate-terminated perfluoropolymer andphosphate-terminated or phosphonate-terminated perfluoropolymerconstitute at least 60% by weight of the electrolyte liquid.

In the same or other embodiments, the electrolyte liquid is between 40%and 70% carbonate-terminated perfluoropolymer by weight, between 5% and25% phosphate-terminated fluoropolymer by weight, the balance of theliquid is the one or more additives, and the balance is between 5% and25% by weight.

In the some embodiments, the electrolyte liquid includes one or moreadditives selected from a conductivity enhancing additive, a viscosityreducer, a high voltage stabilizer, a wettability additive, a flameretardant, or a mixture or combination thereof. In some embodiments, theone or more additives includes a conductivity enhancing additiveselected from ethylene carbonate (EC), propylene carbonate (PC),butylene carbonate (BC), fluoroethylene carbonate, fluoroethylenecarbonate, vinylene carbonate (VC), dimethylvinylene carbonate (DMVC),vinyl ethylene carbonate (VEC), divinylethylene carbonate, phenylethylene carbonate, or diphenyethylene carbonate, γ-butyrolactone, or amixture or combination thereof. In some embodiments, the conductivityenhancing additive constitutes between about 1% to about 30% by weightof the liquid.

In some embodiments, the electrolyte liquid includes one or more cycloalkyl carbonate additives. The cyclo alkyl carbonate may constitute atleast 5% by weight of the liquid, at least 10% by weight of the liquid,at least 15% by weight of the liquid, at least 20% by weight of theliquid, at least 25% by weight of the liquid, or at least 30% by weightof the liquid. Examples of cyclo alkyl carbonates include ethylenecarbonate (EC), fluoroethylene carbonate (FEC), propylene carbonate(PC), and butylene carbonate (BC).

In some embodiments, the carbonate-terminated perfluoropolymer is acarbonate-terminated perfluoropolyether. In some embodiments, thecarbonate-terminated perfluoropolyether corresponds to one of Formula Iand Formula II:

R_(f)—X_(o)—R′  (I)

R″—X_(m)—R_(f)—X_(o)—R′  (II)

-   -   wherein R_(f) is a perfluoropolyether backbone;    -   X is an alkyl, fluoroalkyl, ether, or fluoroether group, wherein        ‘m’ and ‘o’ are each zero or an integer≧1;    -   R′ is a carbonate containing group; and    -   R″ is an aliphatic, alkyl, aromatic, heterocyclic, or carbonate        containing group.

In some embodiments, X includes an ether linkage. In some embodiments, Xis CH₂.

In the same or other embodiments, the carbonate-terminatedperfluoropolyether has two terminal carbonate groups. In someembodiments, the carbonate-terminated perfluoropolyether corresponds toa structure S1 to S4 as depicted further below. In some embodiments, thecarbonate-terminated perfluoropolyether corresponds to Formula I. Insome embodiments, the carbonate-terminated perfluoropolyethercorresponds to a structure S5 to S12 as depicted further below.

In some embodiments, the phosphate-terminated or phosphonate-terminatedperfluoropolymer is a phosphate-terminated or phosphonate-terminatedperfluoropolyether. In some embodiments, the phosphate-terminated orphosphonate-terminated perfluoropolyether comprises Formula I or FormulaII:

R_(f)—X_(o)—R′  (I)

R″—X_(m)—R_(f)—X_(o)—R′  (II)

-   -   wherein R_(f) is a perfluoropolyether backbone;    -   X is an alkyl, fluoroalkyl, ether, or fluoroether group, wherein        ‘m’ and ‘o’ are each independently zero or an integer≧1;    -   R′ is a phosphate or phosphonate containing group; and    -   R″ is an aliphatic, alkyl, aromatic, heterocyclic, phosphate or        phosphonate containing group.

In some embodiments, X includes an ether linkage. In some embodiments, Xis CH₂. In some embodiments, the phosphate or phosphonate containinggroup comprises structure S16 or S17 depicted below. In someembodiments, the phosphate-terminated or phosphonate-terminatedperfluoropolymer corresponds to one of structures P3-P10 depicted below.

Another aspect of the disclosure relates to a battery comprising ananode; a separator; a cathode; a cathode current collector; and any ofthe non-flammable electrolyte compositions disclosed herein. In someembodiments, the cathode current collector comprises aluminum. In someembodiments, the non-flammable electrolyte composition comprises LiTFSI.In some embodiments, the non-flammable electrolyte composition preventsor reduces corrosion of the cathode aluminum current collector ascompared to a reference battery comprising one or more organic carbonatesolvents and LiTFSI, wherein the reference battery does not have afunctionally substituted perfluoropolymer. In some embodiments, thebattery has an operating temperature of about −30° C. to about 150° C.In some embodiments, the non-flammable electrolyte composition preventsor reduces the flammability of the battery as compared to a referencebattery comprising one or more organic carbonate solvents and LiTFSI,wherein the reference battery does not have the functionalizedperfluoropolyether does not have a functionally substitutedperfluoropolymer.

These and other aspects of the disclosure are discussed further below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows ionic conductivity of PFPE-based electrolyte compositionsacross a range of temperatures.

FIG. 2 shows ionic conductivity of PFPE-based electrolyte compositionsat different concentrations of LiTFSI.

FIG. 3 shows a schematic of an example of a coin cell battery.

FIG. 4 shows ionic conductivity of electrolyte solutions across a rangeof temperatures.

FIG. 5 shows ionic conductivity of electrolyte solutions across a rangeof temperatures with either LiPF₆ or LiTFSI salts.

FIG. 6 shows cathodic scan cyclic voltammetry data of a PFPE-basedelectrolyte solution.

FIG. 7 shows anodic scan cyclic voltammetry data of a PFPE-basedelectrolyte solution.

FIG. 8 shows data from high voltage scans of various electrolytesolutions.

FIG. 9 shows cycling performance and stability of PFPE and ethylenecarbonate electrolyte solutions with a graphite-based half-cell in acoin cell battery.

FIG. 10 shows cycling performance and stability of PFPE and ethylenecarbonate electrolyte solutions with a lithium nickel cobalt aluminumoxide (NCA)-based half-cell in a coin cell battery.

FIG. 11 shows cycling performance and stability of PFPE and ethylenecarbonate electrolyte solutions with a lithium iron phosphate(LFP)-based half-cell in a coin cell battery.

FIG. 12 shows conductivity of increasing concentrations of conductivityenhancing additives in various electrolyte solutions.

FIG. 13 shows a comparison of aluminum current collector corrosion in areference electrolyte composition including LiPF₆ and PFPE-basedelectrolyte compositions including LiTFSI.

FIG. 14 shows ionic conductivity of a linear carbonate terminatedPFPE-based electrolyte composition at different concentrations ofLiTFSI.

FIG. 15 shows ionic conductivity of electrolyte solutions across a rangeof temperatures.

FIG. 16 shows cycling performance and stability of a neat linearcarbonate terminated PFPE electrolyte in agraphite/nickel-manganese-cobalt (NMC) cell.

FIG. 17 shows cycling performance and stability of a linear carbonateterminated PFPE-based electrolyte composition in a LTO/NMC cell.

FIG. 18 shows cycling performance and stability of an electrolytecomposition including a PFPE-carbonate and a PFPE-phosphate in agraphite/NMC cell.

DETAILED DESCRIPTION

The following paragraphs define in more detail the embodiments of theinvention described herein. The following embodiments are not meant tolimit the invention or narrow the scope thereof, as it will be readilyapparent to one of ordinary skill in the art that suitable modificationsand adaptations may be made without departing from the scope of theinvention, embodiments, or specific aspects described herein.

Described herein are novel functionally substituted fluoropolymers,non-flammable electrolyte compositions, and alkali metal batteries. Alsodescribed herein are methods for manufacturing the fluoropolymers andcompositions described herein.

For purposes of interpreting this specification, the following terms anddefinitions will apply and whenever appropriate, terms used in thesingular will also include the plural and vice versa. In the event thatany definition set forth below conflicts with any document incorporatedherein by reference, the definition set forth below shall control.

The term “alkyl” as used herein alone or as part of another group,refers to a straight or branched chain hydrocarbon containing any numberof carbon atoms, including from 1 to 10 carbon atoms, 1 to 20 carbonatoms, or 1 to 30 or more carbon atoms and that include no double ortriple bonds in the main chain. Representative examples of alkylinclude, but are not limited to, methyl, ethyl, n-propyl, iso-propyl,n-butyl, sec-butyl, iso-butyl, tert-butyl, n-pentyl, isopentyl,neopentyl, n-hexyl, 3-methylhexyl, 2,2-dimethylpentyl,2,3-dimethylpentyl, n-heptyl, n-octyl, n-nonyl, n-decyl, and the like.“Lower alkyl” as used herein, is a subset of alkyl and refers to astraight or branched chain hydrocarbon group containing from 1 to 4carbon atoms. Representative examples of lower alkyl include, but arenot limited to, methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl,tert-butyl, and the like. The term “alkyl” or “lower alkyl” is intendedto include both substituted and unsubstituted alkyl or lower alkylunless otherwise indicated.

The term “cycloalkyl” as used herein alone or as part of another group,refers to a saturated or partially unsaturated cyclic hydrocarbon groupcontaining from 3, 4 or 5 to 6, 7 or 8 carbons (which carbons may bereplaced in a heterocyclic group as discussed below). Representativeexamples of cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl, and cyclooctyl. These rings may be optionallysubstituted with additional substituents as described herein such ashalo or lower alkyl. The term “cycloalkyl” is generic and intended toinclude heterocyclic groups unless specified otherwise, with examples ofheteroatoms including oxygen, nitrogen and sulfur

The term “alkoxy” as used herein alone or as part of another group,refers to an alkyl or lower alkyl group, as defined herein, appended tothe parent molecular moiety through an oxy group, —O—. Representativeexamples of alkoxy include, but are not limited to, methoxy, ethoxy,propoxy, 2-propoxy, butoxy, tert-butoxy, pentyloxy, hexyloxy and thelike. In some aspects, alkoxy groups, when part of a more complexmolecule, comprise an alkoxy substituent attached to an alkyl or loweralkyl via an ether linkage.

The term “halo” as used herein refers to any suitable halogen, including—F, —Cl, —Br, and —I.

The term “cyano” as used herein refers to a CN group.

The term “hydroxyl” as used herein refers to an —OH group.

The term “sulfoxyl” as used herein refers to a compound of the formula—S(O)R, where R is any suitable substituent such as alkyl, cycloalkyl,alkenyl, alkynyl or aryl.

The term “carbonate” as used herein alone or as part of another grouprefers to a —OC(O)OR radical, where R is any suitable substituent suchas aryl, alkyl, alkenyl, alkynyl, cycloalkyl or other suitablesubstituent as described herein.

The term “cyclic carbonate” as used herein refers to a heterocyclicgroup containing a carbonate.

The term “ester” as used herein alone or as part of another group refersto a —C(O)OR radical, where R is any suitable substituent such as alkyl,cycloalkyl, alkenyl, alkynyl or aryl.

The term “ether” as used herein alone or as part of another group refersto a —COR radical where R is any suitable substituent such as alkyl,cycloalkyl, alkenyl, alkynyl, or aryl.

The term “fluoroalkyl” as used herein alone or as part of another grouprefers to any alkyl substituted with one or more fluorine atoms.

The term “fluoroether” as used herein alone or as part of another grouprefers to a —CF_(n)OCF_(n)R radical, where R is any suitable substituentsuch as alkyl, cycloalkyl, alkenyl, alkynyl or aryl and n is ≧1.

The term “phosphate” as used herein refers to a —OP(O)OR_(a)OR_(b)radical, where R_(a) and R_(b) are independently any suitablesubstituent such as alkyl, cycloalkyl, alkenyl, alkynyl or aryl or ahydrogen atom.

The term “phosphone” as used herein refers to a —P(O)OR_(a)OR_(b)radical, where R_(a) and R_(b) are independently any suitablesubstituent such as alkyl, cycloalkyl, alkenyl, alkynyl or aryl or ahydrogen atom.

The term “nitrile” as used herein refers to a —C≡N group.

The term “sulfonate” as used herein refers to a —S(O)(O)OR radical,where R is any suitable substituent such as alkyl, cycloalkyl, alkenyl,alkynyl or aryl.

The term “sulfone” as used herein refers to a —S(O)(O)R radical, where Ris any suitable substituent such as alkyl, cycloalkyl, alkenyl, alkynylor aryl.

The term “fluoropolymer” as used herein alone or as part of anothergroup refers to a branched or unbranched fluorinated chain including twoor more C—F bonds. The term “perfluorinated” as used herein refers to acompound or part thereof that includes C—F bonds and no C—H bonds. Theterm perfluoropolymer as used herein alone or as part of another grouprefers to a fluorinated chain that includes multiple C—F bonds and noC—H bonds with the exception of C—H bonds that may be present atterminal groups of the chain as described with reference to Formulas Vand VI below.

Examples of fluoropolymers include but are not limited tofluoropolyethers, and perfluoropolyethers (i.e., PFPE(s)),poly(perfluoroalkyl acrylate), poly(perfluoroalkyl methacrylate),polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidenefluoride, and copolymers of any of the forgoing. See, e.g., U.S. Pat.Nos. 8,361,620; 8,158,728 (DeSimone et al.); and U.S. Pat. No.7,989,566, each of which is incorporated by reference herein.

It should be noted that in some embodiments the fluoropolymers describedherein are significantly smaller than conventional polymers, whichcontain many repeated sub-units.

The term “perfluoropolyether” or PFPE as used herein alone or as part ofanother group refers to a chain including two or more ether groups andno C—H bonds with the exception of C—H bonds that may be present atterminal groups of the chain as described with reference to Formulas Vand VI below. Examples include but are not limited to polymers thatinclude a segment such as difluoromethylene oxide, tetrafluoroethyleneoxide, hexafluoropropylene oxide, tetrafluoroethyleneoxide-co-difluoromethylene oxide, hexafluoropropyleneoxide-co-difluoromethylene oxide, or tetrafluoroethyleneoxide-co-hexafluoropropylene oxide-co-difluoromethylene oxide andcombinations thereof. See, e.g., U.S. Pat. No. 8,337,986, which isincorporated by reference herein for its teachings thereof. Additionalexamples include but are not limited to those described in P. Kasai etal., Applied Surface Science 51, 201-211 (1991); J. Pacansky and R.Waltman, Chem. Mater. 5, 486-494 (1993); K. Paciorek and R. Kratzer,Journal of Fluorine Chemistry 67, 169-175 (1994); M. Proudmore et al.,Journal of Polymer Science: Part A: Polymer Chemistry, 33, 1615-1625(1995); J. Howell et al., Journal of Fluorine Chemistry 125, 1513-1518(2004); and in U.S. Pat. Nos. 8,084,405; 7,294,731; 6,608,138;5,612,043; 4,745,009; and 4,178,465, each of which are incorporated byreference herein for their teachings thereof.

The term “functionally substituted” as used herein refers to asubstituent covalently attached to a parent molecule. In some aspectsdescribed herein, the parent molecule is a fluorinated ether orperfluoropolyether as further described herein (e.g., with or without anadditional linking group). In some aspects, the substituent comprisesone or more polar moieties. In some aspects, the presence of thesubstituent (e.g., one or more polar moieties) functions to disassociateand coordinate alkali metal salts under certain conditions as furtherdescribed herein. The term “functionally substituted perfluoropolyether”refers to a compound including a PFPE as described above and one or morefunctional groups covalently attached to the PFPE. The functional groupsmay be directly attached to the PFPE or attached to the PFPE by alinking group. The functional groups and the linking groups, if present,may be non-fluorinated, partially fluorinated, or perfluorinated.

The term “number average molecular weight” or “M_(n)” refers to thestatistical average molecular weight of all molecules (e.g.,perfluoropolyethers) in the sample expressed in units of g/mol. Thenumber average molecular weight may be determined by techniques known inthe art, such as gel permeation chromatography (wherein M_(n) can becalculated based on known standards based on an online detection systemsuch as a refractive index, ultraviolet, or other detector), viscometry,mass spectrometry, or colligative methods (e.g., vapor pressureosmometry, end-group determination, or proton NMR). The number averagemolecular weight is defined by the equation below,

$M_{n} = \frac{\sum{N_{i}M_{i}}}{\sum N_{i}}$

wherein M_(i) is the molecular weight of a molecule and N_(i) is thenumber of molecules of that molecular weight.

The term “weight average molecular weight” or “M_(w)” refers to thestatistical average molecular weight of all molecules (e.g.,perfluoropolyethers), taking into account the weight of each molecule indetermining its contribution to the molecular weight average, expressedin units of g/mol. The higher the molecular weight of a given molecule,the more that molecule will contribute to the M_(w) value. The weightaverage molecular weight may be calculated by techniques known in theart which are sensitive to molecular size, such as static lightscattering, small angle neutron scattering, X-ray scattering, andsedimentation velocity. The weight average molecular weight is definedby the equation below,

$M_{w} = \frac{\sum{N_{i}M_{i}^{2}}}{\sum{N_{i}M_{i}}}$

wherein ‘M_(i)’ is the molecular weight of a molecule and ‘N_(i)’ is thenumber of molecules of that molecular weight.

The term “polydispersity index” or “PDI” refers to the breadth of themolecular weight distribution of a population of molecules (e.g., apopulation of perfluoropolyether molecules). The polydispersity index isdefined by the equation below,

${PDI} = \frac{M_{w}}{M_{n}}$

wherein ‘PDI’ is the ratio of the weight average molecular weight‘M_(w)’ as described herein to the number average molecular weight‘M_(n)’ as described herein. All molecules in a population of molecules(e.g., perfluoropolyethers) that is monodisperse have the same molecularweight and that population of molecules has a PDI or M_(w)/M_(n) ratioequal to 1.

The term “molar mass” refers to the mass of a chemical compound or groupthereof divided by its amount of substance. In the below description,references to weight average molecular weight or number averagemolecular weight may be alternatively taken to be the molar mass of asingle molecule or a population of molecules having a PDI of 1.

The term “non-flammable” as used herein means a compound or solution(e.g., an electrolyte solution) that does not easily ignite, combust, orcatch fire.

The term “flame retardant” as used herein refers to a compound that isused to inhibit, suppress, or delay the spread of a flame, fire, or acombustion of one or more materials.

The term “substantially” as used herein means to a great or significantextent, but not completely. In some aspects, substantially means about90% to 99% or more in the various embodiments described herein,including each integer within the specified range.

The term “about” as used herein refers to any value that is within avariation of up to ±10% of the value modified by the term “about.”

The term “at least about” as used herein refers to a minimum numericalrange of values (both below and above a given value) that has avariation of up to ±10% of the value modified by the term “about.”

As used herein, “a” or “an” means one or more unless otherwisespecified.

Terms such as “include,” “including,” “contain,” “containing,” “has,” or“having” and the like mean “comprising.”

The term “or” can be conjunctive or disjunctive.

Functionally Substituted Fluoropolymers

In some embodiments, the functionally substituted fluoropolymersdescribed herein comprise compounds of Formula I and Formula II:

R_(f)—X_(o)—R′  (I)

R″—X_(m)—R_(f)—X_(o)—R′  (II)

wherein:

R_(f) is a fluoropolymer (e.g., a perfluoropolyether) backbone;

X is an alkyl, fluoroalkyl, ether, or fluoroether group, wherein ‘m’ and‘o’ may each be independently zero or an integer≧1; and

R′ and R″ are each independently functionally substituted aliphatic,alkyl, aromatic, heterocyclic, amide, carbamate, carbonate, sulfone,phosphate, phosphonate, or nitrile containing groups. In some aspects,the fluoropolymer backbone (‘R_(f)’) according to Formula I and FormulaII is a perfluoropolyether (PFPE). In some aspects, the fluoropolymerbackbone (‘R_(f)’) according to Formula I and Formula II may have amolar mass or number average molecular weight (M_(n)) from about 100g/mol to 5,000 g/mol, including each integer within the specified range.In some aspects, the functionally substituted perfluoropolyether (i.e.,R_(f)—X_(o)—R′ or R″—X_(o)—R_(f)—X_(o)—R′) according to Formula I andFormula II may have a molar mass or M_(n) from about 150 g/mol to 5,000g/mol, including each integer within the specified range.

In some embodiments, the functionally substituted fluoropolymersdescribed herein comprise compounds of Formula III and Formula IV:

R_(f)—X_(o)—R′—(X_(t)—R_(a))_(q)  (III)

(R_(b)—X_(s))_(p)—R″—X_(m)—R_(f)—X_(o)—R′—(X_(t)—R_(a))_(q)  (IV)

wherein:

R_(f) is a fluoropolymer (e.g., a perfluoropolyether) backbone;

X is an alkyl, fluoroalkyl, ether, or fluoroether group, wherein ‘s,’‘m’, ‘o’, and ‘t’ may each be independently zero or an integer≧1; and

R′ and R″, and R_(a) and R_(b) are each independently functionallysubstituted aliphatic, alkyl, aromatic, heterocyclic, amide, carbamate,carbonate, sulfone, phosphate, phosphonate, or nitrile containinggroups, wherein ‘p’ and ‘q’ may each be an integer≧1. In some aspects,the fluoropolymer backbone (‘R_(f)’) according to Formula III andFormula IV is a perfluoropolyether. In some aspects, the fluoropolymerbackbone (‘R_(f)’) according to Formula III and Formula IV may have anumber average molecular weight (M_(n)) from about 100 g/mol to 5,000g/mol, or 200 g/mol to 5000 kg/mol, including each integer within thespecified range. In some aspects, the functionally substitutedperfluoropolyether (i.e., R_(f)—X_(o)—R′—(X_(t)—R_(a))_(q) or(R_(b)—X_(s))_(p)—R″—X_(m)—R_(f)—X_(o)—R′—(X_(t)—R_(a))_(q) according toFormula III and Formula IV may have a M_(n) from about 200 g/mol to5,000 g/mol, including each integer within the specified range.

The perfluoropolyether backbone ‘R_(f)’ comprises at least one or morerepeating perfluorinated ether units distributed in any order along apolymer chain comprising: —(CF₂CF(CF₃)O)—, —(CF(CF₃)CF₂O)—, —CF(CF₃)O—,—(CF₂O)—, or —(CF₂CF₂O)—, wherein the sum of the molecular weights ofthe perfluorinated ether units has a number average molecular weightfrom about 100 g/mol to 5,000 g/mol. The repeating perfluorinated etherunits may be the same or different units. For example, a repeating unitmay be the same (e.g., —CF(CF₃)O—, —(CF₂O)—) or different (e.g.,—CF(CF₃)O—, —(CF₂O)—).

In some embodiments, perfluoropolyether backbone (R_(f) of formulasI-IV) described herein comprise an exemplary and non-limitingperfluoropolyether backbone of Formulas V and VI:

wherein:

‘a’, ‘b’, ‘c’, or ‘d’ can each independently be zero or an integer≧1with the proviso that at least one of ‘a’, ‘b’, ‘c’, or ‘d’ is aninteger≧1; wherein the number average molecular weight is from about 150g/mol to about 5,000 g/mol;

T′ is selected from the group consisting of CF₂, CF(CF₃), CF₂X, whereinX is selected from the group consisting of: (CF₂)_(n)CF₃, CH₂,(CH₂)_(n)O, and O, wherein ‘n’ is zero or an integer≧1; and

T″ is selected from the group consisting of: F, CH₂CF₂O, CF₃(CF₂)_(n),CF₃(CF₂)_(n)O, CF(CF₃), (CH₂)_(n), (CH₂)_(n)O, and O, wherein is ‘n’ iszero or an integer≧1.

As described above, for any of a, b, cord that is >1, the multiple—(CF₂CF(CF₃)O)—, —(CF(CF₃)CF₂O)—, —CF(CF₃)O—, —(CF₂O)—, or —(CF₂CF₂O)—ether subunits may be distributed in any order along the chain,including sequentially or interspersed with other ether subunits.

Further examples of functionally substituted fluoropolymers andcomponents thereof according to Formulas I-VI are given below withrespect to structures S1-S41.

A linear fluoropolymer backbone (e.g., ‘R_(f)’ a perfluoropolyetherbackbone of Formulas I-IV or Formulas V and VI) as described hereincomprises at least two carbon atoms. In one aspect, the linearfluoropolymer backbone may comprise between 2 and 100 carbon atoms,including each integer within the specified range. In another aspect,the linear fluoropolymer backbone may comprise between 2 and 50 carbonatoms, including each integer within the specified range. In anotheraspect, the linear fluoropolymer backbone comprises between 2 and 20carbon atoms, including each integer within the specified range. Inanother aspect, the linear fluoropolymer backbone comprises between 2and 10 carbon atoms, including each integer within the specified range.In another aspect, the linear fluoropolymer backbone comprises between 2and 5 carbon atoms, including each integer within the specified range.In another aspect, the linear fluoropolymer backbone comprises 2, 3, 4,5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41,42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59,60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77,78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95,96, 97, 98, 99, or 100 or more carbon atoms.

In some embodiments, one or more repeating units of the main linearfluoropolymer backbone (e.g., ‘R_(f)’ a perfluoropolyether backbone ofFormulas I-IV or Formulas V and VI) may be further substituted with oneor more branching fluorocarbon or fluoroether moieties to form afluorinated branched chain stemming from one or more carbons of the mainfluoropolymer backbone. In one aspect, the one or more branchedfluorinated chains stemming independently from one or more carbon atomsof the linear fluoropolymer backbone may comprise between 1 and 5 carbonatoms, including each integer within the specified range. In anotheraspect, the one or more branched fluorinated chains stemmingindependently from one or more carbon atoms of the linear fluoropolymerbackbone may comprise between 1 and 3 carbon atoms, including eachinteger within the specified range. In another aspect, the one or morebranched fluorinated chains stemming independently from one or morecarbon atoms of the linear fluoropolymer backbone may comprise 1 carbonatom.

One embodiment, described herein is functionalized PFPE comprising twolinear methyl carbonate groups according to Formula VII:

wherein m and n are each independently an integer≧1 and the PFPE mayhave a number average molecular weight (M_(n)) from about 400 g/mol to5,000 g/mol, including each integer within the specified range. In oneaspect, a PFPE according to Formula VII has a number average molecularweight of about 2,000 g/mol.

In some embodiments described herein, the functionalized fluoropolymer(e.g., the perfluoropolyether backbone ‘R_(f)’ covalently attached toone or more groups as described in Formulas I-IV) may have a numberaverage molecular weight (M_(n)) of about 150 g/mol to about 5,000g/mol, including each integer within the specified range. In someaspects, the functionalized fluoropolymer may have a number averagemolecular weight of about 150 g/mol to about 2,000 g/mol, including eachinteger within the specified range. In some aspects, the functionalizedfluoropolymer may have a number average molecular weight of about 150g/mol to about 1,500 g/mol, including each integer within the specifiedrange. In some aspects, the functionalized fluoropolymer may have anumber average molecular weight of about 150 g/mol to about 1,000 g/mol,including each integer within the specified range. In some aspects, thefunctionalized fluoropolymer may have a number average molecular weightof about 150 g/mol to about 500 g/mol, including each integer within thespecified range. In some aspects, the functionalized fluoropolymer mayhave a number average molecular weight of about 150 g/mol to about 300g/mol, including each integer within the specified range. In someaspects, the functionalized fluoropolymer may have a number averagemolecular weight of at least about 150 g/mol, at least about 200 g/mol,at least about 250 g/mol, at least about 300 g/mol, at least about 350g/mol, at least about 400 g/mol, at least about 450 g/mol, at leastabout 500 g/mol, at least about 550 g/mol, at least about 600 g/mol, atleast about 650 g/mol, at least about 700 g/mol, at least about 750g/mol, at least about 800 g/mol, at least about 850 g/mol, at leastabout 900 g/mol, at least about 950 g/mol, at least about 1,000 g/mol,at least about 1,100 g/mol, at least about 1,200 g/mol, at least about1,300 g/mol, at least about 1,400 g/mol, at least about 1,500 g/mol, atleast about 1,600 g/mol, at least about 1,700 g/mol, at least about1,800 g/mol, at least about 1,900 g/mol, at least about 2,000 g/mol, atleast about 2,250 g/mol, at least about 2,500 g/mol, at least about2,750 g/mol, at least about 3,000 g/mol, at least about 3,250 g/mol, atleast about 3,500 g/mol, at least about 3,750 g/mol, at least about4,000 g/mol, at least about 4,250 g/mol, at least about 4,500 g/mol, atleast about 4,750 g/mol, or at least about 5,000 g/mol.

In some embodiments described herein, the functionalized fluoropolymer(i.e., the perfluoropolyether backbone ‘R_(f)’ covalently attached toone or more groups as defined in Formulas I-IV) may have a weightaverage molecular weight (M_(w)) of about 150 g/mol to about 5,000g/mol, including each integer within the specified range. In someaspects, the functionalized fluoropolymer may have a weight averagemolecular weight of about 150 g/mol to about 2,000 g/mol, including eachinteger within the specified range. In some aspects, the functionalizedfluoropolymer may have a weight average molecular weight of about 150g/mol to about 1,500 g/mol, including each integer within the specifiedrange. In some aspects, the functionalized fluoropolymer may have aweight average molecular weight of about 150 g/mol to about 1,000 g/mol,including each integer within the specified range. In some aspects, thefunctionalized fluoropolymer may have a weight average molecular weightof about 150 g/mol to about 500 g/mol, including each integer within thespecified range. In some aspects, the functionalized fluoropolymer mayhave a weight average molecular weight of about 150 g/mol to about 300g/mol, including each integer within the specified range. In someaspects, the functionalized fluoropolymer may have a weight averagemolecular weight of at least about 150 g/mol, at least about 200 g/mol,at least about 250 g/mol, at least about 300 g/mol, at least about 350g/mol, at least about 400 g/mol, at least about 450 g/mol, at leastabout 500 g/mol, at least about 550 g/mol, at least about 600 g/mol, atleast about 650 g/mol, at least about 700 g/mol, at least about 750g/mol, at least about 800 g/mol, at least about 850 g/mol, at leastabout 900 g/mol, at least about 950 g/mol, at least about 1,000 g/mol,at least about 1,100 g/mol, at least about 1,200 g/mol, at least about1,300 g/mol, at least about 1,400 g/mol, at least about 1,500 g/mol, atleast about 1,600 g/mol, at least about 1,700 g/mol, at least about1,800 g/mol, at least about 1,900 g/mol, at least about 2,000 g/mol, atleast about 2,250 g/mol, at least about 2,500 g/mol, at least about2,750 g/mol, at least about 3,000 g/mol, at least about 3,250 g/mol, atleast about 3,500 g/mol, at least about 3,750 g/mol, at least about4,000 g/mol, at least about 4,250 g/mol, at least about 4,500 g/mol, atleast about 4,750 g/mol, at least about 5,000 g/mol, at least about5,500 g/mol, at least about 6,000 g/mol, at least about 6,500 g/mol, atleast about 7,000 g/mol, at least about 7,500 g/mol, at least about8,000 g/mol, at least about 8,500 g/mol, at least about 9,000 g/mol, atleast about 9,500 g/mol, or at least about 10,000 g/mol.

In some embodiments described herein, the functionalized fluoropolymer(e.g., the perfluoropolyether backbone ‘R_(f)’ covalently attached toone or more groups as defined in Formulas I-II) may have apolydispersity index (PDI) of about 1 to about 20. In some aspects, thefunctionalized fluoropolymer may have a polydispersity index of about 1to about 10. In some aspects, the functionalized fluoropolymer may havea polydispersity index of about 1 to about 5. In some aspects, thefunctionalized fluoropolymer may have a polydispersity index of about 1to about 2. In some aspects, the functionalized fluoropolymer may have apolydispersity index of about 1 to about 1.5. In some aspects, thefunctionalized fluoropolymer may have a polydispersity index of about 1to about 1.25. In some aspects, the functionalized fluoropolymer mayhave a polydispersity index of about 1 to about 1.1. In some aspects,the functionalized fluoropolymer may have a polydispersity index ofabout 1, less than about 1.05, less than about 1.1, less than about1.15, less than about 1.2, less than about 1.25, less than about 1.5,less than about 1.75, less than about 2, less than about 2.25, less thanabout 2.5, less than about 2.75, less than about 3, less than about 3.5,less than about 4, less than about 4.5, less than about 5, less thanabout 6, less than about 7, less than about 8, less than about 9, lessthan about 10, less than about 11, less than about 12, less than about13, less than about 14, less than about 15, less than about 16, lessthan about 17, less than about 18, less than about 19, or less thanabout 20.

In some embodiments described herein, the fluoropolymers describedherein (e.g., a functionalized perfluoropolyether) comprises a linearcarbonate terminated PFPE as shown in structure S13 discussed furtherbelow. For example, the linear carbonate terminated PFPE includes amethyl carbonate structure as shown in structure SA1. SA1 is an exampleof R′ or R″ according to some embodiments of Formulas I-II above.

In further examples, in some embodiments, described herein is afunctionalized PFPE comprising two linear methyl carbonate groupsaccording to any of structures S1-S4.

Another embodiment described herein is a functionalized PFPE comprisingone linear methyl carbonate group according to structures S5-S7.

Another embodiment described herein the functionalized PFPE's mayinclude lower alkyl carbonate groups. For example, the methyl carbonategroup of any of structures S5-S7 may be replaced by any of an ethylcarbonate, a propyl carbonate, or a butyl carbonate group. In oneexample, a functionalized PFPE comprising one linear ethyl carbonategroup according to structure S7A is provided:

Another embodiment, described herein is a functionalized PFPE comprisingone cyclic carbonate group according to structures S8-S9.

Another embodiment, described herein is a functionalized PFPE comprisinga linear carbonate group linked to a cyclic carbonate group according tostructure S10.

In another embodiment described herein, the functionalized PFPE maycomprise a linear carbonate structure or cyclic carbonate structure asshown in structures S11A, S11B, S12, wherein one or more carbon atoms ofthe main linear PFPE backbone comprise a branched —CF₃ moiety.

In some embodiments, the fluoropolymers described herein (e.g., afunctionalized perfluoropolyether) may comprise one or more carbamate,carbonate, sulfone, phosphate, phosphonate, or nitrile containinggroups. In some embodiments, these groups may comprise any one of or acombination of any one of the moieties represented by structuresS13-S23. In some embodiments, these groups maybe selected from the groupconsisting of the moieties represented by structures S13-S23. In someaspects, Y′, Y″, and Y′″ represent an additional aliphatic, alkyl,aromatic, heterocyclic, amide, carbamate, carbonate, sulfone, phosphate,phosphonate or nitrile containing groups as given in Formulas I-IVabove. In some embodiments, S13-S23 are examples of R′ or R″ accordingto some embodiments of Formulas I-IV above. In some aspects, themoieties represented by these structures are covalently attached to thefluoropolymer backbone as indicated by Formulas I-IV above.

In some embodiments described herein, the fluoropolymers describedherein (e.g., a functionalized perfluoropolyether) may comprise between1 and 10 of any one of or a combination of any one of the moietiesrepresented by structures S13-S23, including each integer within thespecified range. In some aspects, these structures are covalentlyattached to the perfluoropolyether backbone as indicated by FormulasI-IV above. In some other aspects, the fluoropolymers described herein(e.g., a functionalized perfluoropolyether) may comprise at least 1, atleast 2, at least 3, or at least 4 or more of any one of or acombination of any one of structures S13-S23 covalently attached to thefluoropolymer backbone as indicated by Formulas I-IV above.

In some embodiments described herein, the fluoropolymers describedherein (e.g., a functionalized perfluoropolyether) may comprise any oneof the structures selected from the group consisting of structuresS24-S37 shown below, wherein X is an alkyl, fluoroalkyl, ether, orfluoroether group as defined in Formulas I-IV.

In one embodiment, the functionalized PFPE may comprise an ether linkedcyclic carbonate structure as shown in structures S24-S27,

wherein X is an alkyl, fluoroalkyl, ether, or fluoroether group. Forexample, in S25, the cyclic carbonate is directly attached to the PFPEwithout an X group, and in S26, X is an alkyl group consisting of CH₂,and in S27, X is an alkyl group consisting of CH₂CH₂.

In another embodiment, the functionalized PFPE may comprise a linearcarbonate structure as shown in structures S28 and S29, wherein X is analkyl, fluoroalkyl, ether, or fluoroether group as defined in FormulasI-IV and Y′ is an aliphatic, alkyl, aromatic, heterocyclic, amide,carbamate, carbonate, sulfone, phosphate, phosphonate or nitrilecontaining group. For example, in S29, X is an alkyl ethyl group and Y′is a methyl group, resulting in a linear methyl carbonate structure.

In another embodiment, the functionalized PFPE may comprise a cyclicsulfone structure as show in structure S30. In some aspects, the cyclicsulfone may be multiply substituted as shown in structure S30, wherein Xis an alkyl, fluoroalkyl, ether, or fluoroether group as defined inFormulas I-IV and Y′, Y″, and Y′″ are each independently aliphatic,alkyl, aromatic, heterocyclic, amide, carbamate, carbonate, sulfone,phosphate, phosphonate or nitrile containing groups.

In another embodiment, the functionalized PFPE may comprise a linearsulfone structure as shown in structures S31 and S32, wherein X is analkyl, fluoroalkyl, ether, or fluoroether group as defined in FormulasI-IV and wherein Y′ is an aliphatic, alkyl, aromatic, heterocyclic,amide, carbamate, carbonate, sulfone, phosphate, phosphonate or nitrilecontaining group. For example, in S32, X is an ethyl group and Y′ is anethyl group.

In another embodiment, the functionalized PFPE may comprise aphosphonate structure or phosphate structure as show in structures S33and S34. In some aspects, the phosphonate or phosphate structure may bemultiply substituted, wherein X is an alkyl, fluoroalkyl, ether, orfluoroether group as defined in Formulas I-IV and Y′ and Y″ are eachindependently an aliphatic, alkyl, aromatic, heterocyclic, amide,carbamate, carbonate, sulfone, phosphate, phosphonate or nitrilecontaining group.

Further discussion and examples of functionalized PFPE's includingphosphate or phosphate groups is provided below.

In another embodiment, the functionalized PFPE may comprise an amidegroup as shown in structures S35 and S36, wherein X is an alkyl,fluoroalkyl, ether, or fluoroether group as defined in Formulas I-IV andY′ and Y″ are each independently an aliphatic, alkyl, aromatic,heterocyclic, amide, carbamate, carbonate, sulfone, phosphate,phosphonate or nitrile containing group. In one aspect, X of structure35 connects to the amide group through a carbon (e.g., (R—C)—N). In oneaspect, X of structure 31 may connect through a carbon atom (e.g.,(R—C)—C(O)) or through an oxygen atom (e.g., forming a carbamatestructure (R—O)—C(O)).

In another embodiment, the functionalized PFPE may comprise a nitrilegroup as shown in structure S37, wherein X is an alkyl, fluoroalkyl,ether, or fluoroether group as defined in Formulas I-IV.

According to various embodiments, the functionally substituted PFPEsdescribed herein do not include carbon-carbon double or triple bonds,with carbon-carbon single bonds having greater stability as may bedesirable for an electrolyte solvent.

In some embodiments described herein, the functionally substituted PFPEsdescribed herein serve to coordinate alkali metal ions and exhibitchemical and thermal stability. The relative high fluorine contentreduces or prevents combustion. Further, in some embodiments, thefunctionally substituted PFPEs coordinate alkali metal ions, allowingfor the dissolution of salts, and the conduction of ions in electrolytemixtures as further described herein. In some aspects, the use of anether linkage between the PFPE backbone and any one or more of analiphatic, alkyl, aromatic, heterocyclic, amide, carbamate, carbonate,sulfone, phosphate, phosphonate, or nitrile containing groups as shownby Formulas I-IV or any one or more of structures S13-S23 allows forincreased flexibility and conformational freedom of these groups. Insome aspects, this increased flexibility may enhance the functionalizedperfluoropolyether mediated coordination of alkali metal ions as furtherdescribed herein.

Flammability of an electrolyte compound or mixture thereof may becharacterized by flash points (FPs) or self-extinguishing times (SETs).The flash point of a liquid is the lowest temperature at which vapors ofthe fluid ignite and is measured by subjecting the liquid to an ignitionsource as temperature is raised. The flash point may be tested by usingan instrument, such as the Koehler rapid flash tester, or an equivalent,wherein a composition is subjected to an ignition source for at leastabout 1 second to about 30 seconds at a temperature range of from about−30° C. to about 300° C. A liquid that does not ignite at anytemperature does not have a flash point. It is understood thatreferences to a liquid having a flash point above a certain temperatureinclude liquids that do not have a flash point. The SET of a sample isthe time that an ignited sample keeps burning. In some cases, a liquidmay have a flash point but a SET of zero, indicating that the materialflashes but does not sustain a flame once the ignition source isremoved.

Flammability may also be characterized by a wick test in which a wicksoaked in the electrolyte compound or mixture and ignited with a Bunsenburner for at least 5 seconds. If there is no ignition, the flame isreapplied for at least 10 seconds. The speed at which the flamepropagates is measured. The test may be performed with the wick in ahorizontal or vertical position.

Heavily fluorinated compounds are inherently non-flammable. This isdistinct from conventional electrolyte flame retardant additives such asphosphates, which retard combustion by scavenging free radicals, therebyterminating radical chain reactions of gas-phase combustion.

In some aspects, the functionally substituted fluoropolymer orfluoropolymer backbone R_(f) that is covalently attached to one or moregroups as described in Formulas I-IV is relatively small, with the sizecharacterized by one or more of molar mass, M_(n), M_(w), or main chainlength. In some aspects, a functionalized PFPE as described in FormulasI-VI has R_(f) such that the functionalized PFPE is conductive andinherently non-flammable or has low flammability, as measured by a highor non-existent flash point and a SET of zero. Conductivity of somefunctionally substituted PFPE's drops sharply as the R_(f) sizeincreases, however, if R_(f) (and the F:H ratio) is too small, thecompound may be flammable. PFPEs having R_(f) in the ranges as describedbelow were found to have low or no flammability, and good conductivity.

In some aspects, a perfluoropolyether backbone R_(f) covalently attachedto one or more groups as described in Formulas I-IV has a molar mass ornumber average molecular weight of between about 150 g/mol to 500 g/mol.In some aspects, a perfluoropolyether backbone R_(f) covalently attachedto one or more groups as described in Formulas I-IV has a molar mass ornumber average molecular weight of between about 200 g/mol to 500 g/mol.In some aspects, a perfluoropolyether backbone R_(f) covalently attachedto one or more groups as described in Formulas I-IV has a molar mass ornumber average molecular weight of between about 200 g/mol to about 400g/mol, including each integer within the specified range.

In some aspects, a perfluoropolyether backbone R_(f) covalently attachedto one or more groups as described in Formulas I-IV comprises one ormore perfluorinated ether units distributed in any order along a polymerchain comprising: —(CF₂CF(CF₃)O)—, —(CF(CF₃)CF₂O)—, —CF(CF₃)O—,—(CF₂O)—, or —(CF₂CF₂O)—, wherein the sum of the molar masses ormolecular weights of the perfluorinated ether units has a molar mass ornumber average molecular weight from about 100 g/mol to 450 g/mol,including each integer within the specified range. In some aspects, thesum of the molar masses or molecular weights of the perfluorinated etherunits has a molar mass or number average molecular weight from about 100g/mol to 400 g/mol, including each integer within the specified range.In some aspects, the sum of the molar masses or molecular weights of theperfluorinated ether units has a molar mass or number average molecularweight from about 100 g/mol to 350 g/mol including each integer withinthe specified range. In some aspects, the sum of the molar masses ormolecular weights of the perfluorinated ether units has a molar mass ornumber average molecular weight from about 100 g/mol to 300 g/mol,including each integer within the specified range.

In some embodiments, R_(f) includes a linear fluoropolymer backbone(e.g., a PFPE backbone) having between 3 and 9 carbon atoms includingeach integer in the specified range. For example, the linearfluoropolymer backbone may have between 3 and 8 carbon atoms, or between3 and 7 carbon atoms, or between 3 and 6 carbon atoms, or between 3 and5 atoms. In another aspect the linear fluoropolymer backbone comprises3, 4, 5, 6, 7, 8, or 9 carbon atoms. If branched, the linearfluoropolymer may additionally incorporate one or more branchedfluorinated chains stemming independently from one or more carbon atomsof the linear fluoropolymer backbone as described above, each of whichbranched chains may have between 1 and 5 carbon atoms, including eachinteger within the specified range.

In some embodiments, a PFPE backbone R_(f) covalently attached to one ormore groups as described in Formulas I-IV is unbranched, or if branched,has no branch points within two molecules (along the R_(f)—X—R′ orR″—X_(m)—R_(f)—X—R′ chain) of the functional group on R′ or R″ ofFormulas I and II. In some embodiments, a branched PFPE backbone R_(f)has no branch points within three molecules, four molecules, fivemolecules, or six molecules of the functional group on R′ or R″ ofFormulas I and II. As an example, the branch point C—CF₃ in thestructure S38 below is five molecules away from the carbonate functionalgroup.

In some embodiments, a branched PFPE backbone has no more than twobranches or no more than one branch.

In some embodiments, R′ and R″ as disclosed in Formulas I and II have alower alkyl end group, e.g., R′ or R″ may be methyl carbonate, ethylcarbonate, propyl carbonate, methyl phosphate, ethyl phosphate, etc. Insome embodiments, R′ and R″ as disclosed in Formulas I and II arenon-fluorinated. Fluorine is electron withdrawing such that the presenceof fluorine on R′ or R″ can reduce conductivity. Further, fluorine closeto the carbonate may be unstable. If R′ or R″ is partially fluorinated,any F may be at least two or three molecules away from the carbonate orother functional group of R′ or R″.

In some embodiments, the functionally substituted fluoropolymersdisclosed herein are mono-functional. It has been found that for someembodiments of relatively small molecular weight functionallysubstituted fluoropolymers, mono-functional functionally substitutedfluoropolymers may have significantly higher conductivities than theirdi-functional counterparts, despite having fewer ion coordinatinggroups. Without being bound by a particular theory, it is believed thatthe increase in conductivity is due to the sharp decrease in viscosityobserved for the mono-functional fluoropolymers. For relatively largefunctionally substituted fluoropolymers (e.g., MW of 1000 g/mol andabove), the difference between mono-functional and di-functionalfunctionally substituted fluoropolymers is not expected to be assignificant.

In some embodiments, the functionally substituted fluoropolymersaccording to Formula (I) comprise compounds of Formula (VIII):

R′—X—R_(f) wherein  (VIII)

R′ is a lower alkyl linear carbonate group, X is alkyl, fluoroalkyl,alkoxy, fluoroalkoxy, ether, or fluoroether group, and R_(f) is abranched or unbranched linear perfluoropolyether having a M_(n) ofbetween 200 g/mol and 550 g/mol.

In some embodiments, R′ of Formula VIII is a non-fluorinated lower alkyllinear carbonate group. In some embodiments, R′ is an unsubstitutedlower alkyl linear carbonate group. In some embodiments, R′ is anunbranched lower alkyl linear carbonate group. In some embodiments, R′is ethyl carbonate or methyl carbonate. In some embodiments, R′ ismethyl carbonate according to structure SA1, above.

In some embodiments, X is a non-fluorinated alkyl, alkoxy, or ethergroup. In some embodiments, X is an unsubstituted alkyl, alkoxy, orether group. In some embodiments, X is an unsubstituted alkyl, alkoxy,or ether group having between 1 and 3 carbon atoms. In some embodiments,X is an unsubstituted alkyl, group having between 1 and 3 carbon atoms.In some embodiments X is CH₂, CH₂CH₂, CH₂O, or CH₂CH₂O. In someembodiments, X is CH₂.

In some embodiments, R_(f) has between 3 and 9 carbon atoms. In someembodiments, R_(f) has between 3 and 9 carbon atoms, or between 3 and 8carbon atoms, or between 3 and 7 carbon atoms, or between 3 and 6 carbonatoms, or between 3 and 5 carbon atoms.

In some embodiments, R_(f) has a M_(n) of between 200 g/mol and 500g/mol. In some embodiments, R_(f) has a M_(n) of between 200 g/mol and450 g/mol. In some embodiments, R_(f) has a M_(n) of between 200 g/moland 400 g/mol. In some embodiments, R_(f) has a M_(n) of between 200g/mol and 350 g/mol. In some embodiments, R_(f) has a M_(n) of between200 g/mol and 300 g/mol.

In some embodiments, a compound of Formula VIII has a M_(n) of between250 g/mol and 650 g/mol. In some embodiments, a compound of Formula VIIIhas a M_(n) of between 250 g/mol and 600 g/mol. In some embodiments, acompound of Formula VIII has a M_(n) of between 250 g/mol and 550 g/mol.In some embodiments, a compound of Formula VIII has a M_(n) of between250 g/mol and 500 g/mol. In some embodiments, a compound of Formula VIIIhas a M_(n) of between 250 g/mol and 450 g/mol. In some embodiments, acompound of Formula VIII has a M_(n) of between 250 g/mol and 400 g/mol.In some embodiments, a compound of Formula VIII has a M_(n) of between250 g/mol and 350 g/mol.

In some embodiments, R_(f) comprises one or more perfluorinated etherunits distributed in any order along a chain comprising:—(CF₂CF(CF₃)O)—, —(CF(CF₃)CF₂O)—, —CF(CF₃)O—, —(CF₂O)—, or —(CF₂CF₂O)—.

In some embodiments, R_(f) is terminated with a CF₂CF₂CF₂CF₃ group or aCF₃ group.

Example R_(f) groups of Formula VIII include those of structuresS39-S41:

Examples of substituted PFPE's according to Formula VIII are structuresS5-S7 above.

The functionally substituted fluoropolymers according to Formula VIIImay have the following characteristics: low viscosity, non-flammability,accessible functional groups to dissociate and coordinate alkali metalsalts, relatively high ionic conductivity, and stability. In someembodiments, the viscosity is less than about 10 cP at 20° C. and 1 atm,or less than about 6 cP at 20° C. and 1 atm, or less than about 5 cP at20° C. and 1 atm, or less than about 4 cP at 20° C. and 1 atm, or lessthan about 3 cP at 20° C. and 1 atm. Low viscosity is due tomono-functionality and relatively low molecular weights of thefunctionally substituted PFPE's of Formula VIII.

In some embodiments, the conductivity of a functionally substitutedfluoropolymer according to Formula VIII in 1.0M LiTFSI is at least 0.02mS/cm at 25° C., at least 0.03 mS/cm at 25° C., at least 0.04 mS/cm at25° C., at least 0.05 mS/cm at 25° C., at least 0.06 mS/cm at 25° C., atleast 0.07 mS/cm at 25° C., at least 0.08 mS/cm at 25° C., at least 0.09mS/cm at 25° C., at least 0.10 mS/cm at 25° C., at least 0.11 mS/cm at25° C., at least 0.12 mS/cm at 25° C.

In some embodiments, R′ is an unsubstituted linear carbonate group,which may contribute to high conductivity, with the relatively lowmolecular weights of the PFPE's of Formula VIII also contributing torelatively high conductivity. In some embodiments, a lack of largegroups on either side of the carbonate group of R′ of Formula VIII maycontribute to relatively high conductivity. In some embodiments,relatively small R_(f) groups may contribute to relatively highconductivity.

In some embodiments, the substituted fluoropolymers according to FormulaVIII have a flash point and SET of zero in addition to having theviscosities and/or conductivities described above.

Any of the perfluoropolymers disclosed above with respect to FormulasI-VIII may be modified to form partially fluorinated fluoropolymers. Forexample, one or more CF₃ or CF₂ groups of the PFPE's disclosed hereinmay be modified to form CHF₂, CH₂F, CHF, or CH₂, with the distributionof hydrogen along the R_(f) chain managed to avoid flammability. Suchpartially fluorinated fluoropolymers may be formed from the PFPE or byany other known synthetic route.

Electrolyte Compositions

Some embodiments described herein are electrolyte compositionscomprising a functionally substituted fluoropolymer as described herein.In some aspects, the electrolyte composition comprises a mixture orcombination of functionally substituted fluoropolymers described herein.In some aspects, the electrolyte composition is useful in analkali-metal ion battery. In some aspects, the addition of electrolyteadditives may improve battery performance, facilitate the generation ofa solid electrolyte interface (i.e., an SEI) on electrode surfaces(e.g., on a graphite based anode), enhance thermal stability, protectcathodes from dissolution and overcharging, and enhance ionicconductivity.

In some embodiments, the electrolyte compositions described hereincomprise an alkali metal salt and a functional end group substitutedPFPE as described herein. In some aspects, the electrolyte compositionmay optionally further comprise one or more conductivity enhancingadditives, one or more SEI additives, one or more viscosity reducers,one or more high voltage stabilizers, and one or more wettabilityadditives. In some aspects, the electrolyte compositions describedherein comprise the composition shown in Table 1.

TABLE 1 Example Fluoropolymer Electrolyte System Component ExemplaryComponents Composition Range (%) Alkali-metal salt Lithium salt (e.g.,LiPF₆ or LiTFSI), Sodium  8-35 salt, Potassium salt, etc. Func. Subst.PFPE or PFPE-carbonate (e.g., PFPE-methyl 30-85 mixture of Func. Subst.carbonate) or PFPE-carbonate and PFPE- PFPE's phosphate Conductivityenhancing Ethylene carbonate, fluoroethylene carbonate,  1-40additive(s) trispentafluorophenyl borane, lithium bis(oxalato)borate,γ-butyrolactone, etc. Opt. SEI additive(s) Ethylene carbonate, vinylcarbonate, vinyl 0.5-6   ethylene carbonate, lithium bis(oxalato)borate,lithium difluoro(oxalate)borate, fluoroethylene carbonate, etc. Opt.Viscosity reducer(s) perfluorotetraglyme, γ-butyrolactone,trimethylphosphate, dimethyl methylphosphonate, difluoromethylacetate,0.5-6   fluoroethylene carbonate (FEC), vinylene carbonate (VC), etc.Opt. High voltage 3-hexylthiophene, adiponitrile, sulfolane, 0.5-6  stabilizer(s) lithium bis(oxalato)borate, γ-butyrolactone,1,1,2,2-tetrafluoro-3-(1,1,2,2- tetrafluoroethoxy)-propane, ethyl methylsulfone, trimethylboroxine, etc. Wettability additive Non-ionic or ionicsurfactant, 0.5-6   fluorosurfactant, etc. Opt. Flame retardanttrimethylphosphate, triethylphosphate, 0.5-20  triphenylphosphate,trifluoroethyl dimethylphosphate, tris(trifluoroethyl)phosphate, etc.

Electrolyte compositions described herein can be prepared by anysuitable technique, such as mixing a functionally substitutedfluoropolymer (e.g., a functionalized perfluoropolyether) as describedabove after polymerization thereof with an alkali metal ion salt, andoptionally other ingredients, as described below, in accordance withknown techniques. In the alternative, electrolyte compositions can beprepared by including some or all of the composition ingredients incombination with the reactants for the preparation of the fluoropolymerprior to reacting the same.

When other ingredients are included in the homogeneous solvent system,in general, the functionally substituted fluoropolymer (e.g., afunctionalized perfluoropolyether) is included in the solvent system ina weight ratio to all other ingredients (e.g., polyether, polyethercarbonates) of from 40:60, 50:50, 60:40, or 70:30, up to 90:10, 95:5, or99:1, or more.

In some embodiments, the electrolyte compositions comprise an SEIadditive. In some aspects, the addition of SEI additives prevents thereduction of the PFPE electrolytes described herein and increases thefull cycling of batteries. In some aspects, films of SEI additives maybecoated onto graphite surfaces prior to any cycling to form an insolublepreliminary film. In some aspects, SEI additives form films on graphitesurfaces during the first initial charging when the electrolytecompositions described herein are used in a battery. Suitable SEIadditives comprise polymerizable monomers, and reduction-type additives.

Non-limiting examples include allyl ethyl carbonate, vinyl acetate,divinyl adipate, acrylic acid nitrile, 2-vinyl pyridine, maleicanhydride, methyl cinnamate, phosphonate, 2-cyanofuran, or additionalvinyl-silane-based compounds or a mixture or combination thereof. Inaddition, sulfur-based reductive type additives may be used includingsulfur dioxide, poly sulfide containing compounds, or cyclic alkylsulfites (e.g., ethylene sulfite, propylene sulfite, and aryl sulfites).Other reductive additives including nitrates and nitrite containingsaturated or unsaturated hydrocarbon compounds, halogenated ethylenecarbonate (e.g., fluoroethylene carbonate), halogenated lactones (e.g.,α-bromo-γ-butyrolactone), and methyl chloroformate. Additional examplesmay include a cyclic carbonate having a C═C unsaturated bond, such asvinylene carbonate (VC), dimethylvinylene carbonate (DMVC),vinylethylene carbonate (VEC), divinylethylene carbonate, phenylethylene carbonate, diphenyl ethylene carbonate, or any combinationthereof. In addition, SEI formation maybe initiated by use of carbondioxide as a reactant with ethylene carbonate and propylene carbonateelectrolytes. Additional SEI forming additives may include carboxylphenols, aromatic esters, aromatic anhydrides (e.g., catecholcarbonate), succinimides (e.g., benzyloxy carbonyloxy succinimide),aromatic isocyanate compounds, boron based compounds, such astrimethoxyboroxine, trimethylboroxin, bis(oxalato)borate (e.g., lithiumbis(oxalato) borate (LiBOB)), difluoro(oxalate)borate (e.g., lithiumdifluoro(oxalate)borate (LiDFOB)), or tris(pentafluorophenyl) borane, ormixture or combination thereof. Further examples of SEI additives aretaught by U.S. Patent App. Pub No. 2012/0082903, which is incorporatedby reference herein.

In some embodiments, the electrolyte compositions comprise one or moreflame retardants. Non-limiting examples of flame retardants may includetrimethylphosphate (TMP), triethylphosphate (TEP), Triphenyl phosphate(TPP), trifluoroethyl dimethylphosphate, tris(trifluoroethyl)phosphate(TFP) or mixture or combination thereof. While the electrolyte solutionsdescribed herein are non-flammable, in some embodiments describedherein, one or more flame retardants may be used to prevent, suppress,or delay the combustion of adjacent non-electrolyte materials (e.g.,surrounding battery materials).

In some embodiments, the electrolyte compositions comprise a wettingagent. In some aspects, the wetting agent comprises an ionic ornon-ionic surfactant or low-molecular weight cyclic alkyl compound(e.g., cyclohexane) or an aromatic compound. Other fluoro containingsurfactants may be used. See, U.S. Pat. No. 6,960,410, which isincorporated by reference herein for its teachings thereof

In some embodiments, the electrolyte compositions comprise a non-aqueousconductivity enhancing additive. It is thought that the presence of evensmall amounts of a polar conductivity enhancer aids in thedisassociation of alkali metal salts and increases the totalconductivity of electrolyte mixtures. This may reduce ohmic drop from adecreased bulk resistance in the electrochemical cells of batteries andenable cycling at higher densities. The conductivity enhancing additivemay include, for example, one or more cyclic carbonates, acycliccarbonates, fluorocarbonates, cyclic esters, linear esters, cyclicethers, alkyl ethers, nitriles, sulfones, sulfolanes, siloxanes, and/orsultones.

Cyclic carbonates that are suitable include ethylene carbonate (EC),propylene carbonate (PC), butylene carbonate (BC), fluoroethylenecarbonate and the like. Suitable cyclic esters include, for exampleγ-butyrolactone (GBL), α-methyl-γ-butyrolactone, γ-valerolactone; or anycombination thereof. Examples of a cyclic ester having a C═C unsaturatedbond include furanone, 3-methyl-2(5H)-furanone, α-angelicalactone, orany combinations thereof. Cyclic ethers include tetrahydrofuran,2-methyltetrahydrofuran, tetrahydropyran and the like. Alkyl ethersinclude dimethoxyethane, diethoxyethane and the like. Nitriles includemononitriles, such as acetonitrile and propionitrile, dinitriles such asglutaronitrile, and their derivatives. Sulfones include symmetricsulfones such as dimethyl sulfone, diethyl sulfone and the like,asymmetric sulfones such as ethyl methyl sulfone, propyl methyl sulfoneand the like, and derivatives of such sulfones, especially fluorinatedderivatives thereof. Sulfolanes include tetramethylene sulfolane and thelike.

Other conductivity enhancing carbonates, which may be used, includefluorine containing carbonates, including difluoroethylene carbonate(DFEC), bis(trifluoroethyl) carbonate, bis(pentafluoropropyl) carbonate,trifluoroethyl methyl carbonate, pentafluoroethyl methyl carbonate,heptafluoropropyl methyl carbonate, perfluorobutyl methyl carbonate,trifluoroethyl ethyl carbonate, pentafluoroethyl ethyl carbonate,heptafluoropropyl ethyl carbonate, perfluorobutyl ethyl carbonate, orany combination thereof.

Other conductivity enhancing additives, which may be used, includefluorinated oligomers, dimethoxyethane, triethylene glycol dimethylether (i.e., triglyme), tetraethyleneglycol, dimethyl ether (DME),polyethylene glycols, bromo γ-butyrolactone, fluoro γ-butyrolactone,chloroethylene carbonate, ethylene sulfite, propylene sulfite,phenylvinylene carbonate, catechol carbonate, vinyl acetate, dimethylsulfite, tetraglyme, a crown ether, or any combination thereof.

In some embodiments, the electrolyte composition comprises one or morealkali metal ion salts. Alkali metal ion salts that can be used in theembodiments described herein are also known or will be apparent to thoseskilled in the art. Any suitable salt can be used, including lithiumsalts and sodium salts, and potassium salts, that is, salts containinglithium or sodium or potassium as a cation with a suitable anion. Anysuitable anion may be used, examples of which include, but are notlimited to, boron tetrafluoride, (oxalate)borate,difluoro(oxalate)borate, phosphorus hexafluoride, alkyl sulfonate,fluoroalkyl sulfonate, aryl sulfonate, bis(alkylsulfonyl)amide,perchlorate, bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,alkyl, fluorophosphate, hexafluorophosphate, hexafluoroarsenate,(fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide, nitrate,nitrite, sulfate, hydrogen sulfate, alkyl sulfate, aryl sulfate,carbonate, triflate, bicarbonate, carboxylate, phosphate, hydrogenphosphate, dihydrogen phosphate, hypochlorite, an anionic site of acation-exchange resin, and a mixture of any two or more thereof. Forfurther examples, see, Zhang et al., U.S. Patent Application PublicationNo. 2012/0082903, which is incorporated by reference herein for itsteachings thereof. In some aspects, the alkali metal ion salt is alithium salt.

In some embodiments, the electrolyte compositions described hereincomprise lithium hexafluorophosphate (i.e., LiPF₆). The use of LiPF₆ inlithium ion batteries has demonstrated a balance of important propertiesas an electrolyte salt, particularly in alkali metal batteries. LiPF₆can demonstrate high conductivity and forms stable interfaces and canfunction to passivate the aluminum surface of aluminum-based currentcollectors.

Although common and useful in many applications, the use of LiPF₆ may belimited in certain applications, e.g., under high temperatureconditions. For example, at high temperatures (e.g., >60° C.), thehydrolysis of the PF₆ salt anion can occur leading to the formation ofHF, which is toxic and has deleterious effects on the electrolytesolvent and the electrodes active materials. Hydrolysis of the PF₆ saltanion can further lead to the evolution of gaseous PF₅ and sidereactions with ethylene carbonate to form toxic fluoroethanolderivatives. Therefore, the development of electrolyte compositions thatenable the use of salts having high thermal and electrochemicalstability, while retaining high levels of conductivity is needed.Accordingly, in certain embodiments, it may be useful to employalternative salts in addition to or in replacement of LiPF₆.

Alkali metal sulfonimide salts are exemplary materials that can beemployed for such purposes. Such materials can, in some embodiments,demonstrate sufficient safety at high temperatures, high ionicconductivity, and sufficient thermal and electrochemical stability. Suchproperties can, in some embodiments, render these materials suitableelectrolyte salts for use in lithium ion batteries. Although notintended to be limiting, it is believed that, for example, the enhancedhigh temperature safety, high ionic conductivity, and enhanced thermaland electrochemical stability exhibited by one particular such salt,e.g., bis(trifluoromethanesulfonyl)imide LiN(SO₂CF₃)₂ (LiTFSI), isattributable to the TFSI anion, which demonstrates high thermalstability and decreased hydrolysis from stable C—F bonds.

As further described herein, stable lithium salts include any lithiumsalt, which exhibits low levels of hydrolysis, thermostability, highionic conductivity, and electrochemical stability in electrolytecompositions and in the alkali metal batteries described herein.

Suitable non-limiting sulfonimide salts comprise lithium, sodium,potassium, magnesium, or calcium metal sulfonimide salts, e.g.,comprising lithium bis(trifluoromethanesulfonyl)imide LiN(SO₂CF₃)₂(LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), LiN(FSO₂)₂, lithiumtrifluoromethanesulfonate Li(CF₃)SO₃ (LiTF), lithium(trifluoromethylsulfonyl)(nonafluorobutanesulfonyl)imideLiN(SO₂CF₃)(SO₂C₄F₉), lithium(fluorosulfonyl)(nonafluorobutanesulfonyl)imide LiN(SO₂F)(SO₂C₄F₉),lithium (nonafluoro butan-2-one sulfonyl)(trifluoromethylsulfonyl)imideLiN(SO₂C₂F₄OC₂F₅)(SO₂CF₃), and lithium (nonafluoro butan-2-onesulfonyl)(fluorosulfonyl)imide LiN(SO₂C₂F₄OC₂F₅)(SO₂F).

In some embodiments, the electrolyte compositions described hereinenable the use of lithium sulfonimide salts (e.g., LiTFSI) by minimizingaluminum current collector corrosion. In some aspects, the electrolytecompositions described herein comprise LiTFSI. In some aspects, theelectrolyte compositions described herein comprise a mixture of LiPF₆and LiTFSI.

In some embodiments lithium sulfonamide salts (e.g., LiTFSI) may helpfacilitate the dissolution of highly polar conductivity enhancingadditives, such as ethylene carbonate when used in combination with theperfluoropolyethers described herein. Without being bound by any theory,it is thought that lithium sulfonamide salts (e.g., LiTFSI)substantially disassociate, which increases the ionic strength of theelectrolyte composition allowing for a substantial dissolution of polarcompounds, such as ethylene carbonate.

In some further aspects, the use of a lithium sulfonimide salt (e.g.,LiTFSI) may suppress side reactions on the electrode/electrolyteinterfaces and enable the use of electrolytes at elevated temperaturesgreater than 60° C. leading to increased energy/power characteristicsand use in high temperature applications of the alkali metal batteriesdescribed herein.

In some embodiments, the electrolyte compositions described hereincomprise a viscosity reducer. Suitable, non-limiting examples ofviscosity reducers include perfluorotetraglyme, γ-butyrolactone,trimethylphosphate, dimethyl methylphosphonate, difluoromethylacetate,fluoroethylene carbonate (FEC), vinylene carbonate (VC), etc.

In some embodiments, the electrolyte compositions described hereincomprise a high voltage stabilizer. Suitable non-limiting examples ofhigh voltage stabilizers include 3-hexylthiophene, adiponitrile,sulfolane, lithium bis(oxalato)borate, γ-butyrolactone,1,1,2,2-Tetrafluoro-3-(1,1,2,2-tetrafluoroethoxy)-propane, ethyl methylsulfone, and trimethylboroxine.

In some embodiments, additional ingredients comprising PFPEs andpoly(ethylene oxide) (PEO) may be included in the electrolytecompositions described herein in any suitable amount, such in a weightratio (PFPE:PEO) range of between (on one end of the range) 40:60,50:50, or 60:40, up to (on the other end of the range) 80:20, 90:10 or95:5. In some aspects, the PFPE and PEO may be cross-linked. See, PCTInternational Application Publication No. WO2014062898, which isincorporated by reference in its entirety herein.

In some embodiments, the functionally substituted PFPEs described hereincomprise about 30% to about 85% of the electrolyte compositionsdescribed herein. In some aspects, the functionally substituted PFPEsdescribed herein comprise about 40% to about 50% of the electrolytecompositions described herein. In some aspects, the functionallysubstituted PFPEs described herein comprise about 50% to about 60% ofthe electrolyte compositions described herein. In some aspects, thefunctionally substituted PFPEs described herein comprise about 60% toabout 70% of the electrolyte compositions described herein. In someaspects, the functionally substituted PFPEs described herein compriseabout 70% to about 85% or more of the electrolyte compositions describedherein. In some aspects, the functionally substituted PFPEs describedherein comprise about 35%, about 40%, about 45%, about 50%, about 55%,about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, orabout 90% of the electrolyte compositions described herein.

In some embodiments, the alkali-metal salts described herein compriseabout 8% to about 35% of the electrolyte compositions described herein.In some aspects, the functionally substituted PFPEs described hereincomprise about 20% to about 30% of the electrolyte compositionsdescribed herein. In some aspects the alkali-metal salts describedherein comprise about 10%, about 15%, about 20%, about 25%, about 30%,about 35%, or about 40% of the electrolyte compositions describedherein.

In some embodiments, the optional one or more conductivity enhancingadditives described herein comprise about 1% to about 40% of theelectrolyte compositions described herein. In some aspects, the optionalone or more conductivity enhancing additives described herein compriseabout 10% to about 20% of the electrolyte compositions described herein.In some aspects, the optional one or more conductivity enhancingadditives described herein comprise about 20% to about 30% of theelectrolyte compositions described herein. In some aspects, the optionalone or more conductivity enhancing additives described herein compriseabout 30% to about 40% of the electrolyte compositions described herein.In some aspects, the optional one or more conductivity enhancingadditives described herein comprise about 1%, about 2%, about 3%, about4%, about 5%, about 10%, about 15%, about 20%, about 25%, about 30%,about 35%, about 40%, or about 45% of the electrolyte compositionsdescribed herein.

In some embodiments, the optional one or more SEI additives describedherein comprise about 0.5% to about 6% of the electrolyte compositionsdescribed herein. In some aspects, the optional one or more SEIadditives described herein comprise about 0.5%, about 1%, about 2%,about 3%, about 4%, about 5%, or about 6% of the electrolytecompositions described herein.

In some embodiments, the optional one or more viscosity reducersdescribed herein comprise about 0.5% to about 6% of the electrolytecompositions described herein. In some aspects, the optional one or moreviscosity reducers described herein comprise about 0.5%, about 1%, about2%, about 3%, about 4%, about 5%, or about 6% of the electrolytecompositions described herein.

In some embodiments, the optional one or more high voltage stabilizersdescribed herein comprise about 0.5% to about 6% of the electrolytecompositions described herein. In some aspects, the optional one or morehigh voltage stabilizers described herein comprise about 0.5%, about 1%,about 2%, about 3%, about 4%, about 5%, or about 6% of the electrolytecompositions described herein.

In some embodiments, the optional one or more wettability additivesdescribed herein comprise about 0.5% to about 6% of the electrolytecompositions described herein. In some aspects, the optional one or morewettability additives described herein comprise about 0.5%, about 1%,about 2%, about 3%, about 4%, about 5%, or about 6% of the electrolytecompositions described herein.

Flammability of an electrolytic compound or mixture thereof may becharacterized by flash points (FPs) or self-extinguishing times (SETs).The flash point of a liquid is the lowest temperature at which vapors ofthe fluid ignite and is measured by subjecting the liquid to an ignitionsource as temperature is raised. The flash point may be tested by usingan instrument, such as the Koehler rapid flash tester, or an equivalent,wherein a composition is subjected to an ignition source for at leastabout 1 second to about 30 seconds at a temperature range of from about−30° C. to about 300° C. The SET of a sample is the time that an ignitedsample keeps burning. In some cases, a liquid may have a flash point buta SET of zero, indicating that the material flashes but does not burnonce the ignition source is removed.

Heavily fluorinated compounds are inherently non-flammable. This isdistinct from conventional electrolyte flame retardant additives such asphosphates, which retard combustion by scavenging free radicals, therebyterminating radical chain reactions of gas-phase combustion.

As described above, in some embodiments, the electrolytes disclosedherein have a fluoropolymer or mixture of fluoropolymers as the largestcomponent by weight. This is distinct from fluorinated additives presentin small amounts with non-fluorinated hydrocarbon or other conventionalsolvent as the largest component of the solvent.

In some aspects, the electrolyte compositions described herein comprisethe solvent system shown in Table 2. It should be noted that the solventsystems in Table 2 do not include salts or optional SEI additives, whichmay be added to the solvent to form an electrolyte.

TABLE 2 Example Fluoropolymer Electrolyte Solvent System CompositionRanges Component Example Components (wt %) Func. Subst. PFPE orPFPE-carbonate (e.g., PFPE-methyl  40-100 mixture of Func. Subst.carbonate) or PFPE-carbonate and PFPE 50-90 PFPE' s phosphate 55-8560-70 C1-C10 cycloalkyl Ethylene carbonate, propylene carbonate  0-40carbonate or mixture  5-30 thereof 10-30 15-30 Opt. ConductivityTrispentafluorophenyl borane, lithium 0.5-35  Additive(s), Opt.bis(oxalato)borate, γ-butyrolactone, 0.5-25  Viscosity reducer(s),perfluorotetraglyme, dimethyl 0.5-6   Opt. High voltagemethylphosphonate, stabilizer(s), Opt. difluoromethylacetate,fluoroethylene Wettability additive(s), carbonate (FEC), vinylenecarbonate Opt. Flame retardants (VC), 3-hexylthiophene, adiponitrile,sulfolane, lithium bis(oxalato)borate, γ- butyrolactone,1,1,2,2-tetrafluoro-3- (1,1,2,2-tetrafluoroethoxy)-propane, ethyl methylsulfone, trimethylboroxine, non- ionic or ionic surfactant,fluorosurfactant, trimethylphosphate, triethylphosphate, triphenylphosphate, etc.

In some embodiments, the electrolyte solvent includes a functionallysubstituted PFPE as the largest component by weight and also includes asignificant amount of a C1-C10 cyclo alkyl carbonate. For example, theelectrolyte solvent may include at least 5% by weight, or greater than5% by weight, of C1-C10 cyclo alkyl carbonate such as ethylene carbonate(EC), propylene carbonate (PC), fluoroethylene carbonate (FEC), and thelike. In some embodiments, the electrolyte includes at least 5% of aC1-C10 or C1-C5 cycloalkyl carbonate. In some embodiments, theelectrolyte includes at least 10% of a C1-C10 or C1-C5 cycloalkylcarbonate. In some embodiments, the electrolyte includes at least 15% ofa C1-C10 or C1-C5 cycloalkyl carbonate. In some embodiments, theelectrolyte includes at least 20% of a C1-C10 or C1-C5 cycloalkylcarbonate. In addition to being a conductivity enhancer, the cyclo alkylcarbonate may aid formation of a stable SEI layer.

While EC and other cyclo alkyl carbonates have relatively high FPs, theSETs are also high; once ignited, EC will burn until it is consumed. Itwas unexpectedly found a mixture including a functionally substitutedperfluoropolyether or mixture thereof as the largest component is isinflammable even with a significant amount of a C1-C10 cycloalkylcarbonate. For example, for a 8:2 mixture of a linear PFPE:EC, no FP wasmeasured and the SET was zero.

In some embodiments, the solvent system includes between 0.5% and 25% byweight of γ-butyrolactone. In some embodiments, the solvent systemincludes between 0.5% and 20% by weight of γ-butyrolactone. In someembodiments, the solvent system includes between 0.5% and 15% ofγ-butyrolactone. In some embodiments, the solvent system includesbetween 0.5% and 10% by weight of γ-butyrolactone. In some embodiments,the solvent system includes between 5% and 15% of γ-butyrolactone.

In some embodiments, the solvent system includes between 0.5% and 25% oftrimethylphosphate. In some embodiments, the solvent system includesbetween 0.5% and 20% of trimethylphosphate. In some embodiments, thesolvent system includes between 0.5% and 15% of trimethylphosphate. Insome embodiments, the solvent system includes between 0.5% and 10% oftrimethylphosphate. In some embodiments, the solvent system includesbetween 5% and 15% of trimethylphosphate.

In some embodiments, the electrolyte composition is in accordance withthe examples shown in Table 3.

TABLE 3 Example Fluoropolymer Electrolyte Solvent System CompositionRange Component Example Components (wt %) Lithium salt LiPF₆, LiT SI10-35 10-20 SEI additive Fluoroethylene carbonate, etc. 0-5  5-30 10-30Solvent Mixture of func. subst. PFPE, C1- remainder cycloalkylcarbonate, and optional additives (see Table 2)

As noted above, the PFPE's disclosed herein may have no or very highflash points. The electrolyte solvent including additives will generallyhave a flash point due to the presence of the additives. In someembodiments, the electrolyte compositions described herein arenon-flammable with a flash point greater than about 50° C. to about 275°C. In some aspects, the electrolyte compositions described herein arenon-flammable with a flashpoint greater than about 50° C., greater thanabout 60° C., greater than about 70° C., greater than about 80° C.,greater than about 90° C., greater than about 100° C., greater thanabout 110° C., greater than about 120° C., greater than about 130° C.,greater than about 140° C., greater than about 150° C., greater thanabout 160° C., greater than about 170° C., greater than about 180° C.,greater than about 190° C., greater than about 200° C., greater thanabout 200° C., greater than about 210° C., greater than about 220° C.,greater than about 230° C., greater than about 240° C., greater thanabout 250° C., greater than about 260° C., greater than about 270° C.,or greater than about 280° C. or greater. It is understood that anelectrolyte composition having a flash point greater than a certaintemperature includes compositions that do not ignite and have no flashpoint.

In addition to the flash points described above, the electrolytecompositions may have SETs of less than one second, or zero. It isunderstood that an electrolyte composition having a SET of less than onesecond include electrolyte compositions that have an SET of zero.

The electrolyte compositions may additionally or alternatively becharacterized as having “no sustained flame” on wick test performed asdescribed in the Examples.

In some embodiments, each component of the electrolyte mixture that ispresent at greater than 5% of the solvent has a flash point of at least80° C., or at least 90° C., or at least 100° C. The correspondingelectrolyte mixture may have a flash point of greater than 100° C., orgreater than 110° C., or greater than 120° C., along with an SET ofzero.

In some embodiments, the non-flammable liquid or solid electrolytecompositions described herein have an ionic conductivity of from 0.01mS/cm to about 10 mS/cm at 25° C. In some embodiments, the non-flammableliquid or solid electrolyte compositions described herein have an ionicconductivity of from 0.01 mS/cm to about 5 mS/cm at 25° C. In someembodiments, the non-flammable liquid or solid electrolyte compositionsdescribed herein have an ionic conductivity of from 0.01 mS/cm to about2 mS/cm at 25° C. In some embodiments, the non-flammable liquid or solidelectrolyte compositions described herein have an ionic conductivity offrom 0.1 mS/cm to about 5 mS/cm at 25° C. In some embodiments, thenon-flammable liquid or solid electrolyte compositions described hereinhave an ionic conductivity of from 0.1 mS/cm to about 3 mS/cm at 25° C.In some embodiments, the non-flammable liquid or solid electrolytecompositions described herein have an ionic conductivity of from 0.1mS/cm to about 2 mS/cm at 25° C.

Electrolyte Compositions Including Carbonate Terminated Fluoropolymerand a Phosphate or Phosphonate Terminated Fluoropolymer

In some embodiments, the electrolyte compositions disclosed hereininclude a 1) carbonate terminated fluoropolymer as given by any ofFormulas I-VIII with R′ and, optionally, R″ including a carbonate groupand 2) a phosphate or phosphonate terminated fluoropolymer as given byany of Formulas I-VI with R′ and, optionally, R″ including a phosphateor phosphonate group.

Examples of carbonate terminated fluoropolymers include PFPE's (referredto as PFPE-carbonates) and other perfluoropolymers having linearcarbonate terminated groups as shown in SA1, as well as structuresS1-S13, S24-S29, and S38-S41. Further examples of carbonate terminatedperfluoropolymers include carbonate terminated perfluoropolymersaccording to Formulas I-VI having one or few ether units such as shownin structure S11C:

In some embodiments, the carbonate-terminated fluoropolymer is aperfluoropolyether corresponding to Formula I or Formula II:

R_(f)—X_(o)—R′  (I)

R″—X_(m)—R_(f)—X_(o)—R′  (II)

wherein R_(f) is a perfluoropolyether backbone;X is an alkyl, fluoroalkyl, ether, or fluoroether group, wherein ‘m’ and‘o’ are each zero or an integer≧1;R′ is a carbonate containing group; andR″ is an aliphatic, alkyl, aromatic, heterocyclic, or carbonatecontaining group.

R_(f), X and R″ may be as described above with respect to Formulas I-VI.In some embodiments, the carbonate-terminated fluoropolymer is aperfluoropolyether corresponding to Formula VIII described above.

Examples of phosphate and phosphonate terminated fluoropolymers includePFPE's (referred to as PFPE-phosphates/phosphonates) and otherperfluoropolymers having phosphate or phosphonate end groups as shown inS16, S17, S33 and S34. In one example, the phosphate or phosphonategroup may be according to P1 or P2:

Further examples of functionalized PFPEs comprising a phosphate groupare shown below according to structures P3-P10.

In another example, a functionalized PFPE may comprise one phosphatestructure with a branched PFPE backbone as in the example according tostructure P11.

In another embodiment, a functionalized PFPE may comprise two phosphatestructures according to structure P12.

In some embodiments described herein, the phosphate terminatedfluoropolymers described herein (e.g., a functionalizedperfluoropolyether) may comprise any one or more of the structuresselected from the group consisting of structures P13-P14 shown below,wherein X is an alkyl, fluoroalkyl, ether, or fluoroether group asdefined in Formulas I-IV and Y′ and Y″ are any alkyl fluoroalkyl, ether,or fluoroether containing group. In some aspects, Y′ and Y″ may be partof a ring structure as in structures P8 and P9.

In some embodiments, the phosphate-terminated or phosphonate-terminatedperfluoropolyether corresponds to Formula I or Formula II:

R_(f)—X_(o)—R′  (I)

R″—X_(m)—R_(f)—X_(o)—R′  (II)

wherein R_(f) is a perfluoropolyether backbone;X is an alkyl, fluoroalkyl, ether, or fluoroether group, wherein ‘m’ and‘o’ are each independently zero or an integer≧1;R′ is a phosphate or phosphonate containing group; andR″ is an aliphatic, alkyl, aromatic, heterocyclic, phosphate orphosphonate containing group.

R_(f), X and R″ may be as described above with respect to Formulas I-VI.

In some embodiments, the carbonate terminated fluoropolymer and thephosphate or phosphonate terminated fluoropolymer are according toFormula I-VI with R_(f) being the same for the carbonate terminatedfluoropolymer and the phosphate or phosphonate terminated fluoropolymer.

According to various embodiments, an electrolyte composition having acarbonate terminated fluoropolymer and a phosphate or phosphonateterminated fluoropolymer and one or more additional additives, such asconductivity enhancing additives, in Table 4 below, is miscible even inthe absence of a salt. While the addition of salt improves miscibility,an electrolyte having miscibility in the absence of a salt isadvantageous. Although a PFPE linear carbonate disclosed herein may beable to dissolve lithium salts, conductivities of such electrolytes maybe relatively low compared to conventional electrolytes due to the lowpolarity of the PFPE linear carbonate. As described above, conductivityadditives having high flash points such as EC in fairly significantamounts may be added to increase conductivity while maintaining no orlow flammability.

Depending on the additive(s) and the carbonate terminatedperfluoropolymer, the mixture may not be miscible. The addition of aphosphate terminated or phosphonate perfluoropolymers creates ahomogenous mixture, with the phosphate or phosphonate functionalityinteracting well with polar additives and lithium salts and theperfluoropolymers being fully miscible. Further, the phosphate orphosphonate terminated perfluoropolymer have many or all of the benefitsassociated with the carbonate terminated perfluoropolymers discussedabove, including lack of flammability and relatively high conductivity.

In some aspects, the electrolyte compositions described herein comprisethe solvent system shown in Table 4. It should be noted that the solventsystems in Table 5 do not include salts or optional SEI additives, whichmay be added to the solvent to form an electrolyte.

TABLE 4 Example Fluoropolymer Electrolyte Solvent System CompositionRange Component Example Components (%) Carbonate-terminated PFPEcarbonate, e.g., PFPE-methyl 40-70 perfluoropolymer carbonatePhosphate/phosphonate- PFPE phosphate/phosphonate, e.g.,  5-25terminated PFPE-methyl phosphate perfluoropolymer Conductivity enhancingEthylene carbonate, fluoroethylene  1-40 additive(s) carbonate,trispentafluorophenyl borane,  5-40 lithium bis(oxalato)borate, γ- 10-30butyrolactone, etc. Opt. Viscosity reducer(s) perfluorotetraglyme,γ-butyrolactone, 0.5-6   trimethylphosphate, dimethyl methylphosphonate,difluoromethylacetate, fluoroethylene carbonate (FEC), vinylenecarbonate (VC), etc. Opt. High voltage 3-hexylthiophene, adiponitrile,sulfolane, 0.5-6   stabilizer(s) lithium bis(oxalato)borate,γ-butyrolactone, 1,1,2,2-tetrafluoro-3-(1,1,2,2-tetrafluoroethoxy)-propane, ethyl methyl sulfone, trimethylboroxine,etc. Wettability additive Non-ionic or ionic surfactant, 0.5-6  fluorosurfactant, etc. Opt. Flame retardant trimethylphosphate,triethylphosphate, 0.5-20  triphenylphosphate, trifluoroethyldimethylphosphate, tris(trifluoroethyl)phosphate, etc.

In some embodiments, an electrolyte solvent including a PFPE carbonate(or other carbonate terminated perfluoropolymer), a PFPEphosphate/phosphonate (other phosphate/phosphonate terminatedperfluoropolymer), and one or more additives has the followingcharacteristics: miscible in the absence of a salt, conductive, no orlow flammability, and electrochemically stable. PFPE-carbonates andPFPE-phosphate/phosphonates are conductive and have low or noflammability. PFPE-carbonates are electrochemically stable and have lowviscosity, while PFPE-phosphates/phosphonates improve miscibility ofPFPE-carbonates in mixtures including one or more conductivity enhancingadditives, viscosity reducers, high voltage stabilizers, wettabilityadditives, or flame retardants.

In some embodiments, an electrolyte solvent including a carbonateterminated perfluoropolymer and a phosphate terminated perfluoropolymerinclude a polar additive such as a C1-C10 or C1-C5 cyclo alkylcarbonate. Although a PFPE linear carbonate disclosed herein may be ableto dissolve lithium salts, conductivities of such electrolytes may berelatively low compared to conventional electrolytes due to the lowpolarity of the PFPE linear carbonate. As described above, conductivityadditives having high flash points such as EC in fairly significantamounts may be added to increase conductivity while maintaining no orlow flammability. However, depending on the additive(s) and thecarbonate terminated perfluoropolymer, the mixture may not be misciblein the absence of a salt. An electrolyte having miscibility in theabsence of a salt is advantageous to ensure that during batteryoperation, if there is a salt concentration gradient or salts come outof solution, that the electrolyte composition remains homogenous.

The addition of a phosphate terminated or phosphonate perfluoropolymerscreates a homogenous mixture, with the phosphate or phosphonatefunctionality interacting well with polar additives and lithium saltsand the perfluoropolymers being fully miscible.

In some embodiments, the weight ratio of the carbonate-terminatedperfluoropolymer to the phosphate-terminated or phosphonate-terminatedperfluoropolymer is at least 1.2:1. In some embodiments, the weightratio of the carbonate-terminated perfluoropolymer to thephosphate-terminated or phosphonate-terminated perfluoropolymer is atleast 1.4:1. In some embodiments, the weight ratio of thecarbonate-terminated perfluoropolymer to the phosphate-terminated orphosphonate-terminated perfluoropolymer is at least 1.6:1.

In some embodiments, together the carbonate-terminated perfluoropolymerand phosphate-terminated or phosphonate-terminated perfluoropolymerconstitute at least 50% by weight of the electrolyte liquid. In someembodiments, together the carbonate-terminated perfluoropolymer andphosphate-terminated or phosphonate-terminated perfluoropolymerconstitute at least 60% by weight of the electrolyte liquid. In someembodiments, together the carbonate-terminated perfluoropolymer andphosphate-terminated or phosphonate-terminated perfluoropolymerconstitute at least 60% by weight of the electrolyte liquid.

In some embodiments, the electrolyte liquid is between 40% and 70%carbonate-terminated perfluoropolymer by weight, between 5% and 25%phosphate-terminated fluoropolymer by weight, the balance of the liquidis the one or more additives, and the balance is between 5% and 25% byweight.

In some embodiments, the electrolyte composition is in accordance withthe examples shown in Table 5.

TABLE 5 Example Fluoropolymer Electrolyte Solvent System CompositionRange Component Example Components (wt %) Lithium salt LiPF6, LiTSI10-35 10-20 SEI additive Fluoroethylene carbonate, etc. 0-5  5-30 10-30Solvent Mixture of carbonate-terminated remainder perfluoropolymer,phosphate/phosphonate-terminated perfluoropolymer, conductivityenhancer, and other optional additives (see Table 4)

Alkali Metal Ion Batteries

An alkali metal ion battery (sometimes also referred to as alkali metalbatteries, and including alkali metal-air batteries) of the presentinvention generally includes (a) an anode; (b) a cathode; (c) a liquidor solid electrolyte composition as described above operativelyassociated with the anode and cathode, and (d) optionally a separatorfor physically separating the anode and cathode (See, e.g., M. Armandand J.-M. Tarascon, Building Better Batteries, Nature 451, 652-657(2008)). In addition, alkali metal batteries may further comprise one ormore current collectors at the cathode and anode. Examples of suitablebattery components include but are not limited to those described inU.S. Pat. Nos. 5,721,070; 6,413,676; 7,729,949; and 7,732,100, and inU.S. Patent Application Publication Nos. 2009/0023038; 2011/0311881; and2012/0082930; and S.-W. Kim et al., Adv. Energy Mater. 2, 710-721(2012), each of which is incorporated by reference herein for theirteachings thereof.

Examples of suitable anodes include but are not limited to, anodesformed of lithium metal, lithium alloys, sodium metal, sodium alloys,carbonaceous materials such as graphite, titanium metals, such as, forexample lithium titanium oxide (lithium titanate or LTO) andcombinations thereof. Examples of suitable cathodes include, but are notlimited to cathodes formed of transition metal oxides, doped transitionmetal oxides, metal phosphates, metal sulfides, lithium iron phosphate,and combinations thereof. See, e.g., U.S. Pat. No. 7,722,994, which isincorporated by reference herein for its teachings thereof. Additionalexamples include but are not limited to those described in Zhang et al.,U.S. Pat. App. Pub No. 2012/0082903, at paragraphs 178 to 179, which isincorporated by reference herein for its teachings thereof. In someembodiments, an electrode such as a cathode can be a liquid electrode,such as described in Y. Lu et al., J Am. Chem. Soc. 133, 5756-5759(2011), which is incorporated by reference herein for its teachingsthereof. Numerous carbon electrode materials, including but not limitedto carbon foams, fibers, flakes, nanotubes and other nanomaterials,etc., alone or as composites with each other or other materials, areknown and described in, for example, U.S. Pat. Nos. 4,791,037;5,698,341; 5,723,232; 5,776,610; 5,879,836; 6,066,413; 6,146,791;6,503,660; 6,605,390; 7,071,406; 7,172,837; 7,465,519; 7,993,780;8,236,446, and 8,404,384, each of which is incorporated by referenceherein for its teachings thereof. In an alkali metal-air battery such asa lithium-air battery, sodium-air battery, or potassium-air battery, thecathode is preferably permeable to oxygen (e.g., where the cathodecomprises mesoporous carbon, porous aluminum, etc.), and the cathode mayoptionally contain a metal catalyst (e.g., manganese, cobalt, ruthenium,platinum, or silver catalysts, or combinations thereof) incorporatedtherein to enhance the reduction reactions occurring with lithium ionand oxygen at the cathode. See, e.g., U.S. Pat. No. 8,012,633 and U.S.Patent Application Publication Nos. 2013/0029234; 2012/0295169;2009/0239113; see also P. Hartmann et al., A rechargeableroom-temperature sodium superoxide (NaO₂) battery, Nature Materials 12,228-232 (2013), each of which is incorporated by reference herein forits teachings thereof.

Where the electrolyte composition is a liquid composition, a separatorformed from any suitable material permeable to ionic flow can also beincluded to keep the anode and cathode from directly electricallycontacting one another. Examples of suitable separators include, but arenot limited to, porous membranes or films formed from organic polymersor polyolefin based separators, such as polypropylene, polyethylene,etc., including composites thereof. The useful separators may furtherhave a coating, for example, a ceramic coating (e.g., a polyolefin basedseparator with a ceramic coating) or a PVDF coating. See generally P.Arora and Z. Zhang, Battery Separators, Chem. Rev. 104, 4419-4462(2004), which is incorporated by reference herein for its teachingsthereof. When the electrolyte composition is a solid composition,particularly in the form of a film, it can serve as its own separator.Such solid film electrolyte compositions of the present invention may beof any suitable thickness depending upon the particular battery design,such as from 0.01, 0.02, 0.1 or 0.2 microns thick, up to 1, 5, 7, 10,15, 20, 25, 30, 40 or 50 microns thick, or more.

The alkali metal batteries described herein may also include one or morecurrent collectors at the cathode and one or more current collectors atthe anode. Suitable current collectors function to transfer a largecurrent output while having low resistance. Current collectors describedherein may be, for example, in the form of a foil, mesh, or as anetching. Furthermore, a current collector may be in the form of amicrostructured or a nanostructured material generated from one or moresuitable polymers. Suitable atomic materials comprise Cu, Fe, Ni, or Ti.In some aspects, the current collectors may be aluminum (Al) at thecathode. Because lithium may react with Al at low potentials, copper(Cu) is typically used at the anode.

Aluminum-based cathodic current collectors are widely used because oftheir excellent conductivity, high mechanical strength, high ductility,and affordability in commercial settings. Despite these aspects,passivation of the aluminum current collectors is generally necessary toprevent corrosion and diminished cell performance. For example, thelithium salt LiPF₆ forms stable interfaces and leads to passivation ofthe aluminum surface of aluminum-based current collectors (understood tooccur by partial decomposition of the lithium salt and oxidation ofmetallic aluminum at high potentials, forming a dense film of AlF₃ onthe top of the air-formed surface layer of Al₂O₃). While, thisprotective layer reduces the level of corrosion, aluminum stillundergoes a slow corrosion, which in certain cases can be a limitingfactor in alkali metal battery performance (e.g., when 5 V class cathodematerials are used). Aluminum current collector corrosion may bedetermined by methods known in the art, see, for example, Kramer et al.,Electrochemistry Letters. 1(5) 2012 and Zhang et al., Journal of TheElectrochemical Society. 152 (11) 2005, which is incorporated byreference herein for its teachings thereof.

It is well established that sulfonimide-based salts, such as LiTFSI,generally do not properly passivate aluminum-based current collectorswith insoluble fluorinated species. Again, although not intending to belimited by theory, it is believed that this is likely due to thestability of the TFSI anion. This lack of passivation eventually leadsto severe aluminum current collector corrosion (aluminum dissolution) atpotentials higher than 3.5 V leading to decreased contact of the cathodeand the aluminum current collector, electrode degradation and rapid cellfading.

Thus, it was surprisingly found that the functionalized PFPE-based solidor liquid electrolyte compositions described herein prevent or reducethe corrosion of aluminum-based current collectors in alkali metalbatteries, enabling the use of highly stable lithium salts (e.g.,LiTFSI). Similar to how LiPF₆ functions to passivate aluminum, andwithout being bound by any theory, it is believed that thefunctionalized PFPEs described herein react with aluminum and form athin passivating film, which protects aluminum from future oxidativecorrosion. Although not intended to be limiting, in some aspects, thismay occur by formation of an insoluble protective AlF₃ layer as a resultof PFPE oxidation and aluminum dissolution in the very beginning of thecell charging process. In some other aspects, this may occur by theformation of an Al(TFSI)₃ protective layer, which is insoluble in thePFPE based electrolyte compositions described herein.

Therefore, in some embodiments described herein, the PFPE-based solid orliquid electrolyte compositions described herein can prevent or reducecorrosion of aluminum based current collectors. In some aspects, thePFPE-based solid or liquid electrolyte compositions prevent or reducealuminum current collector corrosion and permit the use of any stablealkali metal salt described herein, including those that do notpassivate aluminum. In some aspects, the PFPE-based solid or liquidelectrolyte compositions described herein comprising a lithiumsulfonimide salt prevent or reduce aluminum current collector corrosion.In one aspect, the PFPE-based solid or liquid electrolyte compositionsdescribed herein comprising a LiTFSI prevent or reduce aluminum currentcollector corrosion.

In some embodiments, the use of a stable lithium salt as describedherein (e.g., LiTFSI) in the functionalized PFPE-based solid or liquidelectrolyte compositions described herein further decreases theflammability of the electrolyte composition. In some aspects, thecombination of a stable lithium salt with PFPE-based electrolytecompositions as described herein further reduces the flammability of theelectrolyte composition as compared to a PFPE-based electrolytecomposition alone. In some aspects, the use of a stable lithium salt(e.g., LiTFSI) with a PFPE-based electrolyte composition as describedherein reduces gas build up and eventual rupture or gaseous explosionrisk of a susceptible alkali metal battery.

In some embodiments, the use of a stable lithium salt as describedherein (e.g., LiTFSI) in the functionalized PFPE-based solid or liquidelectrolyte compositions described herein in an alkali metal batteryincreases the potential operating temperature of the battery withoutincurring battery failure. In one aspect, the operating temperature maybe from about −30° C. to about 150° C., including each integer withinthe specified range. In another aspect, the operating temperature may befrom about −30° C. to about 50° C., including each integer within thespecified range. In another aspect, the operating temperature may befrom about −30° C. to about 100° C., including each integer within thespecified range. In another aspect, the operating temperature may befrom about −30° C. to about 150° C., including each integer within thespecified range. In another aspect, the operating temperature may befrom about −10° C. to about 150° C., including each integer within thespecified range. In another aspect, the operating temperature may befrom about 0.0° C. to about 150° C., including each integer within thespecified range. In another aspect, the operating temperature may befrom about 70° C. to about 200° C., including each integer within thespecified range. In another aspect, the operating temperature may befrom about 90° C. to about 200° C., including each integer within thespecified range. In another aspect, the operating temperature may befrom about 110° C. to about 200° C., including each integer within thespecified range. In another aspect, the operating temperature may befrom about 140° C. to about 200° C., including each integer within thespecified range. In another aspect, the operating temperature may befrom about 180° C. to about 200° C., including each integer within thespecified range. In another aspect, the operating temperature may befrom about 180° C. to about 200° C., including each integer within thespecified range. In another aspect, the upper limit of the batteryoperating temperature may be at least about 50° C., at least about 60°C., at least about 70° C., at least about 80° C., at least about 90° C.,at least about 100° C., at least about 110° C., at least about 120° C.,at least about 130° C., at least about 140° C., or at least about 150°C. In another aspect, the lower limit of the battery operatingtemperature may be at least about −30° C., at least about −20° C., atleast about −10° C., at least about 0° C., at least about 10° C., or atleast about 20° C.

All components of the battery can be included in or packaged in asuitable rigid or flexible container with external leads or contacts forestablishing an electrical connection to the anode and cathode, inaccordance with known techniques.

It will be readily apparent to one of ordinary skill in the relevantarts that suitable modifications and adaptations to the compositions,methods, and applications described herein can be made without departingfrom the scope of any embodiments or aspects thereof. The compositionsand methods provided are exemplary and are not intended to limit thescope of the specified embodiments. All of the various embodiments,aspects, and options disclosed herein can be combined in all variations.The scope of the compositions, formulations, methods, and processesdescribed herein include all actual or potential combinations ofembodiments, aspects, options, examples, and preferences hereindescribed. All patents and publications cited herein are incorporated byreference herein for the specific teachings thereof.

EXAMPLES Example 1 Synthesis of a Cyclic PFPE Carbonate

A 250 mL round bottom flask equipped with a stir bar was charged with50.0 g (0.091 mole) of 1H,1H-perfluoro-3,6,9-trioxatridecan-1-ol, 4.01 g(0.100 mole) of sodium hydroxide and 84 g (71 mL, 0.91 mole) ofepichlorohydrine, sealed and placed in an oil bath thermostated at 60°C. The reaction was stopped after 18 hrs, the unreacted epichlorohydrinwas removed using rotary evaporator and the residue was diluted with 300mL of ethyl acetate. The solution was washed with water (2×150 mL) andbrine (150 mL), the aqueous layer was extracted with ethyl acetate (100mL) and combined organic fractions were dried over magnesium sulfate.The filtrate was concentrated and distilled under reduced pressureobtaining 36.5 g (0.059 mole) of the product with 64.6% yield.

A 250 mL Schenk flask equipped with a stir bar was charged with 35.0 g(0.058 mole) of2-(1H,1H,3H,3H-perfluoro-2,5,8,11-tetraoxapentadecyl)oxirane, 0.98 g(2.4 mmole) of methyltriphenylphosphonium iodide and 40 mL of1-methoxy-2-propanol. Next, a balloon was attached to the flask, filledwith carbon dioxide and the reaction was run at room temperature forfour days. During that time the balloon was refilled several times tomaintain the positive pressure of carbon dioxide in the vessel. Thesolvent was removed using rotary evaporator, the residue was dissolvedin ethyl acetate (200 mL), washed with water (2×100 mL) and brine (100mL), dried over magnesium sulfate and concentrated in vacuo. The residuewas vacuum distilled to remove unreacted starting materials. The crudeproduct was recrystallized from ethanol giving 15.65 g (0.024 mole) of4-(1H,1H,3H,3H-perfluoro-2,5,8,11-tetraoxapentadecyl)-1,3-dioxolan-2-one(S8) as white crystals. Yield of the reaction was 41.7%.

Example 2 Synthesis of a Linear PFPE Carbonate According to Structure S2

100 g 1H, 1H, 11H,11H-Perfluoro-3,6,9-trioxaundecan-1,11-diol, 75 mLEt3N and 500 mL 1,1,1,3,3-pentafluorobutane are mixed in a 1 L roundbottom flask containing 20 g activated 3 Å sieves. This solution isallowed to sit for 24 hours over the sieves. The solution is transferredunder nitrogen, via cannula, into a 1 L 3-neck round bottom flask. Oneneck has a gas adaptor connected to a nitrogen source, one neck has a100 mL pressure-equalized addition funnel and the remaining neck has aseptum which is used for the cannula transfer. The reaction vessel isimmersed in an ice-bath and the addition funnel is charged with 38 mLmethyl chloroformate and 50 mL 1,1,1,3,3-pentafluorobutane. Thechloroformate solution is added dropwise over the course of an hour tothe reaction vessel. Once addition is complete the ice-bath is removedand the reaction stirred at room temperature for four hours. Thesolution is filtered, and then washed with 500 mL 5% HCl and 2×500 mL DIwater. The solution is then dried with MgSO4, filtered, and the1,1,1,3,3-pentafluorobutane and any other volatiles removed by rotaryevaporation. The resulting colorless oil distilled under vacuum at 200millitorr. The slightly yellow oil which is left behind is saved to becombined with future batches and re-distilled as it is found to containmostly desired product. The material is dried for 2 days over 20 g 3 Åactivated molecular sieves before use.

Example 2A Synthesis of a Linear PFPE Carbonate According to StructureS7

A 2 L round bottom flask was charged with 192 mL (1.376 mole) oftriethylamine, 350.2 g (1.241 mole) of1H,1H-nonafluoro-3,6-dioxaheptan-1-ol, 1.25 L of1,1,1,3,3-pentafluorobutane and 3 Å molecular sieves, then sealed anddried overnight. A 3 L, three-neck, jacketed round bottom flask wasequipped with a gas adapter, addition funnel and an overhead mechanicalstirrer. The flask was purged with nitrogen and cooled with and icewater. Next, the dried solution was transferred to the reaction flaskvia cannula needle, and allowed to cool down before proceeding to thenext step. 105 mL (1.366 mole) of methyl chloroformate in 100 mL of dry1,1,1,3,3-pentafluorobutane was transferred to the addition funnel,followed by a dropwise addition to the vigorously stirred reactionmixture over 2 hours. Upon the addition, the reaction mixture wasallowed to warm up to room temperature and stirred for additional 2hours. Afterwards, the precipitate was filtered off, washed with1,1,1,3,3-pentafluorobutane, and the filtrate was concentrated in vacuo.The residual organic layer was washed with water (2×200 mL) and brine(1×200 mL), dried with anhydrous magnesium sulfate and the solvent wasremoved. The crude product was vacuum distilled, obtaining 375.0 g(1.103 mole) of 1H,1H-nonafluoro-3,6-dioxaheptanyl methyl carbonate as aclear, colorless liquid with 89.0% yield (25° C./0.1-0.2 Torr).

Example 2B Synthesis of a Linear PFPE Carbonate According to StructureS8

A 2 L round bottom flask was charged with 192 mL (1.376 mole) oftriethylamine, 350.2 g (1.241 mole) of1H,1H-nonafluoro-3,6-dioxaheptan-1-ol, 1.25 L of1,1,1,3,3-pentafluorobutane and 3 Å molecular sieves, then sealed anddried overnight. A 3 L, three-neck, jacketed round bottom flask wasequipped with a gas adapter, addition funnel and an overhead mechanicalstirrer. The flask was purged with nitrogen and cooled with and icewater. Next, the dried solution was transferred to the reaction flaskvia cannula needle, and allowed to cool down before proceeding to thenext step. 105 mL (1.366 mole) of methyl chloroformate in 100 mL of dry1,1,1,3,3-pentafluorobutane was transferred to the addition funnel,followed by a dropwise addition to the vigorously stirred reactionmixture over 2 hours. Upon the addition, the reaction mixture wasallowed to warm up to room temperature and stirred for additional 2hours. Afterwards, the precipitate was filtered off, washed with1,1,1,3,3-pentafluorobutane, and the filtrate was concentrated in vacuo.The residual organic layer was washed with water (2×200 mL) and brine(1×200 mL), dried with anhydrous magnesium sulfate and the solvent wasremoved. The crude product was vacuum distilled, obtaining 375.0 g(1.103 mole) of 1H,1H-nonafluoro-3,6-dioxaheptanyl methyl carbonate as aclear, colorless liquid with 89.0% yield (25° C./0.1-0.2 Torr).

Example 3 Dissolution of Ethylene Carbonate in a Carbonate TerminatedPFPE

Carbonate-terminated PFPE materials and ethylene carbonate areimmiscible but experience salt-induced miscibility upon introduction ofcertain lithium salts. It was found that 1.0M LiPF₆ dissolved in alinear PFPE carbonate according to structure S2 (also referred to astetra-dMe) is immiscible with EC at any concentration; however 1.0MLiTFSI is miscible up to at least 30 wt % EC. Without being bound by anytheory, this is likely due to the more complete dissociation of LiTFSIversus LiPF₆ in the PFPE. The enhanced dissociation increases the ionicstrength of the solution, which made it more favorable for the highlypolar ethylene carbonate to dissolve.

Example 4 Electrochemical Measurements

The conductivity of electrolyte compositions and cyclic voltammetrymeasurements of perfluoropolyether based electrolyte compositions weredetermined experimentally using similar methods as described by Teran etal., Solid State Ionics (2011) 203, p. 18-21; Lascaud et al.,Maromolecules (1994) 27 (25); and International Patent ApplicationPublication Nos. WO2014/204547 and WO2014/062898, each of which areincorporated by reference herein for their teachings thereof.

Example 5 Temperature-Dependent Ionic Conductivity of PerfluoropolyetherBased Electrolyte Compositions

As shown in FIG. 1, the conductivity of electrolyte compositionscomprising a linear carbonate terminated perfluoropolyether according tostructures S2, S3, S7 and a perfluoropolyether with a structureaccording to Formula VII having a number average molecular weight ofabout 2,000 g/mol (also referred to as D10H-dMe) and 1.0M LiTFSIdecreases across a range of temperatures.

Example 6 Conductivity of PFPE's

The conductivity of several perfluoropolyethers according to structuresS2, S3, S5, S6, S7, S11 and a perfluoropolyether with a structureaccording to Formula VII having a number average molecular weight ofabout 2,000 g/mol (also referred to as D10H-dMe) as a function of LiTFSIsalt concentration was measured. As shown in FIG. 2, the conductivityincreases with increasing LiTFSI content.

Example 7 Coin Cell Battery Testing of Electrolyte Compositions

Coin cell batteries as depicted by the schematic in FIG. 3 werefabricated for testing of electrolyte compositions.

Example 8 Temperature-Dependent Ionic Conductivity of a Linear PFPECarbonate and Ethylene Carbonate Containing Electrolyte Solution

As shown in FIG. 4, the conductivity of electrolyte solutions containinga linear carbonate terminated PFPE according to structure S2 (alsoreferred to as tetra-dMe) decreases with across a range of temperatures.It was found that increasing concentration of ethylene carbonateincreases the conductivity across a range of temperatures. Similarresults were observed with either LiPF₆ or LiTFSI salts at a 1.0 Mconcentration (FIG. 5).

Example 9 Cyclic Voltammetry of a Linear PFPE Carbonate ContainingElectrolyte Solution

The electrochemical stability of a linear carbonate terminated PFPEaccording to structure S2 (also referred to as tetra-dMe) with 1.0 MLiTFSI was tested and demonstrated electrochemical stability. FIG. 6shows the cathodic scan on a glassy carbon working electrode at 25° C.and FIG. 7 shows the anodic scan on a Pt working electrode at 25° C.

Example 10 High Voltage Scan of Electrolyte Solutions

A voltage sweep to 7V on a Pt working electrode (a lithium referenceelectrode and a Pt counter electrode) with a linear carbonate terminatedPFPE according to structure S2 (also referred to as tetra-dMe) in 1.0 MLiTFSI compared to other conventional electrolyte systems is shown inFIG. 8. Accordingly, the highly fluorinated backbone of the PFPE impartsoxidative stability for PFPE based electrolytes.

Example 11 Cycling Performance and Stability of Active Materials in CoinCell Batteries

The performance of a linear carbonate terminated PFPE according tostructure S2 (also referred to as tetra-dMe) supplemented with 10%ethylene carbonate with different half-cell materials was tested. Thecycling experiments were carried out at room temperature with 1.0MLiTFSI. PFPE neat compositions without ethylene carbonate were cycled ata C/10 discharge rate, whereas compositions containing ethylenecarbonate were cycled at a C/5 discharge rate.

As shown in FIG. 9, the presence of 10% ethylene carbonate improved thecycling performance of graphite based coin cells even at the C/5discharge rate. The cycling performance of lithium nickel cobaltaluminum oxide (NCA) based half cells with a PFPE and 10% ethylenecarbonate electrolyte solution with LiTFSI was similar to a commercialelectrolyte solution with LiPF₆, whereas the PFPE neat compositiondemonstrated a decrease in discharge capacity after about 30 cycles FIG.10. As shown in FIG. 11, the discharge capacity of a LFP half-cell isconstant for 40 cycles for the PFPE neat composition with 1.0 M LiTFSI;these data represents a still cycling coin cell at 40 cycles. The PFPEcomposition supplemented with 10% ethylene carbonate maintained aconstant discharge capacity for about 100 cycles.

Example 12 Conductivity of Conductivity Enhancing Additives

The conductivity of a linear carbonate terminated PFPE according tostructure S2 (also referred to as tetra-dMe) supplemented withincreasing concentrations of tetraglyme, crown ether, or ethylenecarbonate with 1.0 M LiTFSI was tested. As shown in FIG. 12, therelative conductance of the electrolyte solutions increased withaddition of each additive.

Example 13 Perfluoropolyether Mediated Suppression of Aluminum Corrosion

The suppression of aluminum corrosion in an electrolyte compositionhaving LiTFSI and a linear perfluoropolyether according to structure S7was tested. These experiments were performed by holding a constantvoltage in a coin cell with an aluminum working electrode and a lithiummetal counter/reference electrode. Any current observe is assumed to bethe corrosion of the aluminum. The lower the current, the less corrosionis occurring. The extent of aluminum corrosion in electrolytecompositions with PFPEs and LiTFSI (curves A-C) was compared to areference standard electrolyte standard composition of LiPF₆ in amixture of ethylene carbonate/ethyl methyl carbonate (EC/EMC) (E) asshown in FIG. 13. The corrosion current values observed in thePFPE-based electrolyte compositions are lower than those observed in thereference electrolyte composition (E), which is widely used incommercial cells and known to suppress aluminum corrosion. Aluminumundergoes severe corrosion in the reference organic carbonate-basedelectrolyte composition (D).

Example 14 Conductivities and Flash Points of Linear PFPE-Carbonates

Flash points and conductivities of unbranched, linear PFPE-carbonates ofvarious sizes were measured.

Mono- Number Conductivity or MW of Flash 1.0M LiTFSI di- of carbonsPoint @ 25° C. Molecule functional R_(f) in R_(f) (° C.) (mS/cm) D10H-di about >20 None did not solvate dME 1800 1.0M LiTFSI S2 di 348 6 1800.03 S3 di 232 4 154 0.04 S5 mono 517 9 None 0.02 S6 mono 401 7 None*0.04 S7 mono 251 4 None* 0.12

S2 and S3 differ only by the presence of a —(CF₂CF₂O)— subunit, as do S5and S6. Comparing S2 and S3, the conductivity of S3 is 50% greater thanthat of S2. Comparing S5 and S6, the conductivity of S6 is twice that ofS5. Based on these results, it is expected that increasing the size ofS2 or S5 would show lower or no conductivity. S6 differs from S7 by thepresence of a terminal butyl rather than a terminal methyl chain, withconductivity of S7 three times that of S6. These results indicate thatthe size of R_(f), which may be characterized by molar mass (ormolecular weight) or number of carbons, is critical for conductivity.

In this and other examples, the presence of an asterisk (*) on flashpoint measurements indicates that while the sample did not exhibit atraditional ‘flash’ and failed to trigger the detector, at temperaturesabove 100° C. a small green flame was sometimes visible directly on theelectric heating coil of the flash-point tester as it glowed red hot anddipped into the vapor space. It is believed that this is due todecomposition of the material directly on the coil, which achievestemperatures in excess of 1000° C., rather than ignition of the vapors.

Example 15 Conductivities and Flash Points of Branched PFPE Carbonates

Flash points and conductivities of branched linear PFPE-carbonates ofvarious sizes were measured.

Conduc- tivity Mono- 1.0M or MW Number of Flash LiTFSI di- of carbonsPoint @ 25° C. Molecule functional R_(f) in R_(f) (° C.) (mS/cm) S11Amono 617 11 (8 along None None main chain) S11B mono 451 8 (6 along NoneNone main chain) S11C mono 285 5 (4 along None 0.05 main chain)

These results indicate that the size of R_(f), which may becharacterized by molar mass (or molecular weight) or number of carbons,is critical for conductivity. In addition, unbranched PFPE-carbonatesare more conductive than similarly sized branched PFPE-carbonates. Thisis unexpected, as the unbranched PFPE-carbonates would be expected to bemore viscous, and less conductive than branched PFPE-carbonates. Withoutbeing bound by a particular theory, it is believed that branched chainsthat are too close to the carbonate or other functional group stericallyhinder Li ion coordination with the functional group.

Example 16 Conductivities and Flash Points of Linear PFPE-CarbonatesHaving Different R′ Groups

Flash points and conductivities of branched linear PFPE-carbonates ofvarious sizes were measured.

Conductivity Flash Point 1.0 M LiTFSI @ 25° C. Molecule (° C.) (mS/cm)S7 120 0.12 S7A (S7 with ethyl carbonate end group)  

 88 0.09 S7 with trifluoroethyl carbonate end group  

None None (does not dissolve 0.1 M salt)

Notably, the PFPE with a methyl carbonate end group has higherconductivity and is less flammable than the PFPE with an ethyl carbonateend group, though the conductivity of the ethyl carbonate is still high.Adding fluorine to the carbonate end group results in a less flammablecompound that does not dissolve 1.0 M LiTFSI.

Example 17 Conductivity of a Linear Carbonate PFPE as a Function of SaltConcentration and Temperature

Conductivity of solution of S7 with LiTFSI salt was measured as afunction of salt concentration and temperature. Results are in FIGS. 14and 15. FIG. 15 shows that the conductivity is increased with theaddition of 10% EC.

Example 18 Cycling Performance and Stability of Linear Carbonate PFPE inCoin Cell Batteries

The performance of a linear carbonate terminated PFPE according tostructure S7 was tested on a graphite/nickel-manganese-cobalt (NMC)cell. The S7 solution was neat (with the addition of 2% FEC as an SEIadditive for the graphite cathode). The cycling experiment was carriedout at room temperature with 1.0M LiTFSI. Formation rate was C/20 andcycling rate was C/10. FIG. 16 shows that the cycling is stable and thatthe pure linear carbonate terminated PFPE can be used as a sole solvent(with the addition of a SEI additive if using a graphite anode) in alithium ion electrode.

The performance of a linear carbonate terminated PFPE according tostructure S7 was tested on a LTO/NMC cell. The electrolyte solvent was8:2 (by weight) S7:EC. The cycling experiment was carried out at roomtemperature with 1.2M LiTFSI. Formation rate was C/10 and cycling ratewas 1 C. FIG. 17 shows stable cycling over 400 cycles.

Example 19 Conductivity, Viscosity, and Flash Point of Mono-FunctionalVs. Di-Functional Linear Carbonate Terminated PFPEs

Flash points, viscosities and conductivities of mono- and di-functionalPFPE-carbonates of various sizes were measured.

Mono- Conductivity or di- Viscosity Flash 1.0M LiTFSI Mol- func- R_(f)(cP) at Point @ 25° C. ecule tional MW MW 20° C. (° C.) SET (mS/cm) S2di 526 348 21 180 None 0.03 S3 di 410 232 23 154 None 0.04 S5 mono 606517 5.6 None  None 0.02 S6 mono 490 401 4.0 None* None 0.04 S7 mono 340251 2.5 None* None 0.12

S3 and S7 are directly comparable, with the S7 being the mono-carbonateversion of S3. In an unexpected result, the conductivity of S7 is threetimes that of its di-functional counterpart.

Example 20 Small Molecule Carbonates

Flash points, SETs, and conductivities of heavily fluorinated smallmolecule carbonates were measured.

Conductivity 1.0 M Mono- or LiTFSI @ di- Flash Point SET 25° C. Moleculefunctional MW R_(f) MW (° C.) (S) (mS/cm) 1,1,1,3,3,3-hexafluoropropan-2-yl methyl carbonate  

mono 226 69 None None Dissolves only 0.2 M salt, barely conductsbis(2,2,2-trifluoroethyl) carbonate  

mono 226 69 None None Does not dissolve salts methyl 2,2,2-trifluoroethyl carbonate  

mono 158 69 40 3 .83

The heavily fluorinated small molecule carbonates are non-conductive orhighly flammable.

Example 21 Non-Fluorinated Carbonates

Flash points, SETs and conductivities of non-fluorinated carbonates weremeasured.

Conductivity 1.0 M Mono- or LiTFSI @ di- Flash Point SET 25° C. Moleculefunctional MW (° C.) (S) (mS/cm) heptyl methyl carbonated  

mono 174 128 75 1.45 2-(2-methoxyethoxy)ethyl methyl carbonate  

mono 178  87 90 0.49

These are conductive, but very flammable.

Example 22 Conductivity, Flash Point and SET of Electrolyte MixturesIncluding PFPEs

The conductivities, flash points and SETs of the two electrolytemixtures including PFPE's were determined and compared against a controlelectrolyte of EC:EMC.

Flash Conductivity Salt Point SET 1.0M LiTFSI Formulation (1.0M) (° C.)(S) @ 25° C. (mS/cm) S7:P3:EC:other LiTFSI 128 — 1.77 additives(50:15:15:20) S7:EC (8:2) LiTFSI None* — 0.84 EC:EMC (3:7) LiPF₆ 27 long9.6

Example 23 Wick Tests of Electrolyte Mixtures Including PFPEs

3″ long, ¼″ diameter silica wicks were soaked in the electrolyteformulation and ignited with a Bunsen burner for 5 seconds. If there isno ignition, the flame was reapplied for 10 seconds. The speed at whichthe flame propagates the wick is measured. The test was performed withthe wick in both the vertical and horizontal directions.

Horizontal Wick Vertical Wick Salt Composition Test Test 1.0M LiPF₆EC:EMC (1:1) 5.3 mm/sec 38.1 mm/sec 1.0M LiTFSI S2 No sustained flame1.0M LiTFSI S2:EC (9:1) No sustained flame 0.8M LiTFSI S2:GBL:EC (7:2:1)0.3 mm/sec 3.62 mm/sec 1.2M LiTFSI S7:EC (8:2) No sustained flame

Example 24 Cycling Performance and Stability of Electrolyte Including aPFPE-Phosphate and a PFPE-Carbonate in a Coin Cell Battery

The performance of an electrolyte including a PFPE-carbonate accordingto structure S7 and a PFPE-phosphate according to structure P3 wastested on a graphite/NMC cell. The S7 solution was neat (with theaddition of 2% FEC as an SEI additive for the graphite cathode). Theelectrolyte solvent was 50:15:35 S7:P3:other additives including EC. Thesalt was 0.8M LiTFSI, 2% wt LiDFOB. Formation rate was C/20 and cyclingrate was 1 C. FIG. 18 shows that the cycling is stable.

Example 25 Miscibility of Electrolyte Solvents IncludingCarbonate-Terminated Perfluoropolymers

A mixture of S7, EC, other additives (55/15/20, wt) is not homogeneousin the absence of dissolved salt. Introduction of 10 wt % P3 resolvesthe issue and the mixture of S7/EC/other additives/P3 (55/15/20/10, wt)is homogeneous with and without dissolved lithium salt.

Example 26 Synthesis of Ether-Linked Phosphate SubstitutedPerfluoropolyethers Synthesis of 1H,1H-Perfluoro-3,6,9-TrioxatridecanylDimethyl Phosphate (P10)

A 500 mL round bottom flask was charged with 50.0 g of1H,1H-perfluoro-3,6,9-trioxatridecan-1-ol (0.091 mole), 13.4 mL (0.096mole) of triethylamine, 250 ml of 1,1,1,3,3-pentafluorobutane andmolecular sieves. The reaction mixture was dried overnight andsubsequently transferred to a 500 mL Schlenk flask via cannula needle.The flask was equipped with a pressure equalized addition funnel, placedunder nitrogen and cooled to 0° C. 13.3 mL (0.096 mole) of dimethylchlorophosphate in 10 mL dry 1,1,1,3,3-pentafluorobutane was addeddropwise, the reaction was continued at room temperature for additional18 hours. Afterwards, the mixture was filtered, washed with 5%HCl_(aq.), water and brine, then dried with anhydrous magnesium sulfate.The solvent was removed using rotary evaporator, and the product wasisolated via a distillation under reduced pressure. 13.6 g (0.021 mole,25% yield) of 1H,1H-perfluoro-3,6,9-trioxatridecanyl dimethyl phosphatewas collected as a higher boiling clear, colorless fraction.

Synthesis of 1H,1H-Nonafluoro-3,6-Dioxaheptanyl Dimethyl Phosphate (P3)

A 250 mL Schlenk flask equipped with a pressure equalized additionfunnel was charged with 4.45 g (0.186 mole) of sodium hydride (orpotassium tert-butoxide) and 150 mL of anhydrous THF, then placed underinert atmosphere and stirred at 0° C. 51.3 g (0.182 mole) of1H,1H-nonafluoro-3,6-dioxaheptan-1-ol was added dropwise to the mixtureover 1 hour, then stirred at room temperature for additional 20 minutes.A 500 mL three-neck, round bottom flask was charged with 20.0 mL (0.186mole) of dimethyl chlorophosphate and 300 mL anhydrous THF. The reactionflask was flushed with nitrogen and cooled in an IPA-dry ice bath to −40to −30° C. A pressure equalized addition funnel was connected to theflask. The solution of sodium 1H,1H-nonafluoro-3,6-dioxaheptan-1-oxidewas added dropwise to the reaction mixture while maintaining thetemperature of the cooling bath. Upon addition, the reaction was stirredat room temperature for 1 hour. Afterwards, 5 mL of water and 100 mL1,1,1,3,3-pentafluorobutane were injected, the mixture was filtered, andsolvents were removed using rotary evaporator.1H,1H-nonafluoro-3,6-dioxaheptanyl dimethyl phosphate was isolated via adistillation under reduced pressure, collecting 60.9 g (0.156 mole, 84%yield) clear, colorless liquid (40-45° C./0.09-0.2 Torr fraction).

Example 27 Conductivity, Flammability, and Viscosity of PFPE-Phosphates

The conductivity, flash point, SET, and viscosity of structures P3 andP10 was determined.

Conductivity 1.0M Viscosity LiTFSI @ (cP) at Flash Point SET 25° C.Molecule MW 20° C. (° C.) (S) (mS/cm) P10 656 17 None None 0.07 P3 3906.7 None None .37

What is claimed is:
 1. A non-flammable electrolyte compositioncomprising: an electrolyte liquid comprising a functionally substitutedperfluoropolyether according to Formula VIII:R′—X—R_(f)  (VIII) wherein R′ is an unsubstituted lower alkyl linearcarbonate group, X is an unsubstituted alkyl, alkoxy, or ether group,and R_(f) is a branched or unbranched linear perfluoropolyether having amolar mass of between 200 g/mol and 550 g/mol; and an alkali metal salt.2. The non-flammable electrolyte composition of claim 1, wherein thefunctionally substituted perfluoropolyether comprises about 30% to about85% of the electrolyte composition.
 3. The non-flammable electrolytecomposition of claim 1, wherein the functionally substitutedperfluoropolyether comprises about 40% to about 85% of the electrolytecomposition.
 4. The non-flammable electrolyte composition of claim 1,wherein the functionally substituted perfluoropolyether comprises is thelargest component by weight of the electrolyte solvent.
 5. Thenon-flammable electrolyte composition of claim 1, wherein R_(f) is abranched or unbranched linear perfluoropolyether having a molar mass ofbetween 200 g/mol and 450 g/mol.
 6. The non-flammable electrolytecomposition of claim 1, wherein R_(f) is a branched or unbranched linearperfluoropolyether having a molar mass of between 200 g/mol and 300g/mol.
 7. The non-flammable electrolyte composition of claim 1, whereinthe functionalized perfluoropolyether molar mass of between 250 g/moland 650 g/mol.
 8. The non-flammable electrolyte composition of claim 1,wherein R′ is methyl carbonate.
 9. The non-flammable electrolytecomposition of claim 1, wherein R_(f) has no more than two ether units.10. The non-flammable electrolyte composition of claim 1, wherein R_(f)has two at least two ether subunits independently selected from—(CF₂CF(CF₃)O)—, —(CF(CF₃)CF₂O)—, —CF(CF₃)O—, —(CF₂O)—, or —(CF₂CF₂O)—.11. The non-flammable electrolyte composition of claim 1, wherein thefunctionalized perfluoropolyether exhibits a viscosity of less than 10cP at 20° C. and 1 atm.
 12. The non-flammable electrolyte composition ofclaim 1, wherein X is a lower alkyl group.
 13. The non-flammableelectrolyte composition of claim 1, wherein the functionally substitutedperfluoropolyether is selected from one of:


14. The non-flammable electrolyte composition of claim 1, wherein thealkali metal salt comprises a lithium salt or a sodium salt.
 15. Thenon-flammable electrolyte composition of claim 14, wherein the alkalimetal salt is a lithium salt comprising LiPF₆ or LiTFSI or a mixturethereof.
 16. The non-flammable electrolyte composition of claim 1,wherein the electrolyte liquid further comprises further comprising oneor more of a conductivity enhancing additive, viscosity reducer, a highvoltage stabilizer, a wettability additive, or a flame retardant, or amixture or combination thereof.
 17. The non-flammable electrolytecomposition of claim 1, wherein the electrolyte liquid further comprisesa conductivity enhancing additive selected from ethylene carbonate (EC),propylene carbonate (PC), butylene carbonate (BC), fluoroethylenecarbonate, γ-butyrolactone, or a mixture or combination thereof.
 18. Thenon-flammable electrolyte composition of claim 17, wherein theconductivity enhancing additive comprises about 1% to about 40% of thenon-flammable electrolyte composition.
 19. The non-flammable electrolytecomposition of claim 17, wherein the conductivity enhancing additivecomprises about 5% to about 40% of the non-flammable electrolytecomposition.
 20. The non-flammable electrolyte composition of claim 17,wherein the electrolyte liquid comprises a high voltage stabilizerselected from 3-hexylthiophene, adiponitrile, sulfolane, lithiumbis(oxalato)borate, γ-butyrolactone,1,1,2,2-Tetrafluoro-3-(1,1,2,2-tetrafluoroethoxy)-propane, ethyl methylsulfone, or trimethylboroxine or a mixture or combination thereof. 21.The non-flammable electrolyte composition of claim 17, wherein theelectrolyte liquid comprises a wettability additive selected fromtriphenyl phosphite, dodecyl methyl carbonate, methyl 1-methylpropylcarbonate, methyl 2,2-dimethylpropanoate, or phenyl methyl carbonate ora mixture or combination thereof.
 22. The non-flammable electrolytecomposition of claim 17, wherein the electrolyte liquid comprises aflame retardant additive selected from trimethylphosphate,triethylphosphate, triphenyl phosphate, trifluoroethyldimethylphosphate, tris(trifluoroethyl)phosphate, or mixture orcombination thereof.
 23. The non-flammable electrolyte composition ofclaim 17, wherein the viscosity reducer, high voltage stabilizer, andwettability additive each independently comprise about 0.5-6% of thenon-flammable liquid or solid electrolyte composition and the flameretardant comprises about 0.5-20% of the non-flammable liquid or solidelectrolyte composition.
 24. The non-flammable electrolyte compositionof claim 1, wherein the electrolyte liquid further comprises a phosphateor phosphonate-terminated perfluoropolymer.
 25. The non-flammableelectrolyte composition of claim 1, wherein the electrolyte compositionhas a flash point greater than 100° C.
 26. The non-flammable electrolytecomposition of claim 1, wherein the electrolyte composition has a flashpoint greater than 110° C.
 27. The non-flammable electrolyte compositionof claim 1, wherein the electrolyte composition has a flash pointgreater than 120° C.
 28. The non-flammable electrolyte composition ofclaim 1, the electrolyte composition has self-extinguishing time ofzero.
 29. The non-flammable electrolyte composition of claim 1, whereinthe composition does not ignite when heated to a temperature of about150° C. and subjected to an ignition source for at least 15 seconds. 30.The non-flammable electrolyte composition of claim 1, wherein thecomposition has an ionic conductivity of from 0.01 mS/cm to about 10mS/cm at 25° C.
 31. The non-flammable electrolyte composition of claim1, wherein the composition has an ionic conductivity of from 0.1 mS/cmto 3 mS/cm at 25° C.
 32. A battery comprising: an anode; a separator; acathode; at least one cathode current collector; and the non-flammableelectrolyte composition according to claim
 1. 33. The battery of claim32, wherein the at least one cathode current collector comprisesaluminum.
 34. The battery according to claim 33, wherein thenon-flammable electrolyte composition comprises LiTFSI.
 35. The batteryaccording to claim 34, wherein non-flammable electrolyte compositionprevents or reduces corrosion of the cathode aluminum current collectoras compared to a reference battery comprising one or more organiccarbonate solvents and LiTFSI, wherein the reference battery does nothave a functionally substituted perfluoropolymer.
 36. The battery ofclaim 32, wherein the battery has an operating temperature of about −30°C. to about 150° C.
 37. The battery of claim 32, wherein thenon-flammable electrolyte composition prevents or reduces theflammability of the battery as compared to a reference batterycomprising one or more organic carbonate solvents and LiTFSI, whereinthe reference battery does not have the functionalizedperfluoropolyether does not have a functionally substitutedperfluoropolymer.